diff --git a/source/game.cpp b/source/game.cpp
index 5afb464..085fd93 100644
--- a/source/game.cpp
+++ b/source/game.cpp
@@ -1,14 +1,15 @@
 #include "game.h"
-#include <SDL2/SDL_blendmode.h>	  // for SDL_BLENDMODE_BLEND
-#include <SDL2/SDL_keycode.h>	  // for SDLK_1, SDLK_2, SDLK_3, SDLK_h
-#include <SDL2/SDL_pixels.h>	  // for SDL_PIXELFORMAT_RGBA8888
-#include <SDL2/SDL_rwops.h>		  // for SDL_RWFromFile, SDL_RWclose, SDL_R...
-#include <SDL2/SDL_timer.h>		  // for SDL_GetTicks
-#include <SDL2/SDL_video.h>		  // for SDL_WINDOWEVENT_FOCUS_GAINED, SDL_...
-#include <stdlib.h>				  // for rand
-#include <algorithm>			  // for min
-#include <fstream>				  // for basic_ifstream
-#include <iostream>				  // for char_traits, basic_istream, ifstream
+#include <SDL2/SDL_blendmode.h> // for SDL_BLENDMODE_BLEND
+#include <SDL2/SDL_keycode.h>	// for SDLK_1, SDLK_2, SDLK_3, SDLK_h
+#include <SDL2/SDL_pixels.h>	// for SDL_PIXELFORMAT_RGBA8888
+#include <SDL2/SDL_rwops.h>		// for SDL_RWFromFile, SDL_RWclose, SDL_R...
+#include <SDL2/SDL_timer.h>		// for SDL_GetTicks
+#include <SDL2/SDL_video.h>		// for SDL_WINDOWEVENT_FOCUS_GAINED, SDL_...
+#include <stdlib.h>				// for rand
+#include <algorithm>			// for min
+#include <fstream>				// for basic_ifstream
+#include <iostream>				// for char_traits, basic_istream, ifstream
+#include <numeric>
 #include "asset.h"				  // for Asset
 #include "background.h"			  // for Background
 #include "balloon.h"			  // for Balloon, BALLOON_SPEED_1, BALLOON_...
@@ -133,13 +134,13 @@ void Game::init(int player_id)
 	players_.push_back(std::move(player2));
 
 	// Obtiene mediante "playerID" el jugador que va a empezar jugar
-	auto player = getPlayer(player_id);
+	auto main_player = getPlayer(player_id);
 
 	// Cambia el estado del jugador seleccionado
-	player->setStatusPlaying(PlayerStatus::PLAYING);
+	main_player->setStatusPlaying(PlayerStatus::PLAYING);
 
 	// Como es el principio del juego, empieza sin inmunidad
-	player->setInvulnerable(false);
+	main_player->setInvulnerable(false);
 
 	// Variables relacionadas con la dificultad
 	switch (difficulty_)
@@ -243,9 +244,9 @@ void Game::init(int player_id)
 		// Activa o no al otro jugador
 		if (rand() % 2 == 0)
 		{
-			const auto otherPlayer = player_id == 1 ? 2 : 1;
-			auto player = getPlayer(otherPlayer);
-			player->setStatusPlaying(PlayerStatus::PLAYING);
+			const auto other_player_id = player_id == 1 ? 2 : 1;
+			auto other_player = getPlayer(other_player_id);
+			other_player->setStatusPlaying(PlayerStatus::PLAYING);
 		}
 
 		for (auto &player : players_)
@@ -707,7 +708,7 @@ bool Game::saveDemoFile(const std::string &file_path)
 #endif // RECORDING
 
 // Crea una formación de enemigos
-void Game::deployEnemyFormation()
+void Game::deployBalloonFormation()
 {
 	// Solo despliega una formación enemiga si ha pasado cierto tiempo desde la última
 	if (balloon_deploy_counter_ == 0)
@@ -1587,14 +1588,8 @@ void Game::killPlayer(std::shared_ptr<Player> &player)
 // Calcula y establece el valor de amenaza en funcion de los globos activos
 void Game::evaluateAndSetMenace()
 {
-	menace_current_ = 0;
-	for (auto &balloon : balloons_)
-	{
-		if (balloon->isEnabled())
-		{
-			menace_current_ += balloon->getMenace();
-		}
-	}
+	menace_current_ = std::accumulate(balloons_.begin(), balloons_.end(), 0, [](int sum, const auto &balloon)
+									  { return sum + (balloon->isEnabled() ? balloon->getMenace() : 0); });
 }
 
 // Obtiene el valor de la variable
@@ -1645,11 +1640,11 @@ void Game::updateTimeStoppedCounter()
 }
 
 // Actualiza la variable enemyDeployCounter
-void Game::updateEnemyDeployCounter()
+void Game::updateBalloonDeployCounter()
 {
 	if (balloon_deploy_counter_ > 0)
 	{
-		balloon_deploy_counter_--;
+		--balloon_deploy_counter_;
 	}
 }
 
@@ -1750,7 +1745,7 @@ void Game::update()
 
 			// Actualiza los contadores de estado y efectos
 			updateTimeStoppedCounter();
-			updateEnemyDeployCounter();
+			updateBalloonDeployCounter();
 
 			// Actualiza el ayudante
 			updateHelper();
@@ -1872,7 +1867,7 @@ void Game::updateMenace()
 	if (menace_current_ < menace_threshold_)
 	{
 		// Crea una formación de enemigos
-		deployEnemyFormation();
+		deployBalloonFormation();
 
 		// Recalcula el nivel de amenaza con el nuevo globo
 		evaluateAndSetMenace();
@@ -2248,28 +2243,14 @@ void Game::run()
 // Indica si se puede crear una powerball
 bool Game::canPowerBallBeCreated()
 {
-	if ((!power_ball_enabled_) && (calculateScreenPower() > POWERBALL_SCREENPOWER_MINIMUM) && (power_ball_counter_ == 0))
-	{
-		return true;
-	}
-
-	return false;
+	return (!power_ball_enabled_) && (calculateScreenPower() > POWERBALL_SCREENPOWER_MINIMUM) && (power_ball_counter_ == 0);
 }
 
 // Calcula el poder actual de los globos en pantalla
 int Game::calculateScreenPower()
 {
-	auto power = 0;
-
-	for (auto &balloon : balloons_)
-	{
-		if (balloon->isEnabled())
-		{
-			power += balloon->getPower();
-		}
-	}
-
-	return power;
+	return std::accumulate(balloons_.begin(), balloons_.end(), 0, [](int sum, const auto &balloon)
+						   { return sum + (balloon->isEnabled() ? balloon->getPower() : 0); });
 }
 
 // Inicializa las variables que contienen puntos de ruta para mover objetos
@@ -2354,7 +2335,7 @@ void Game::updateHelper()
 	// Solo ofrece ayuda cuando la amenaza es elevada
 	if (menace_current_ > 15)
 	{
-		for (auto &player : players_)
+		for (const auto &player : players_)
 		{
 			helper_.need_coffee = (player->getCoffees() == 0);
 			helper_.need_coffee_machine = (!player->isPowerUp());
@@ -2370,7 +2351,7 @@ void Game::updateHelper()
 bool Game::allPlayersAreWaitingOrGameOver()
 {
 	auto success = true;
-	for (auto &player : players_)
+	for (const auto &player : players_)
 	{
 		success &= player->isWaiting() || player->isGameOver();
 	}
@@ -2382,7 +2363,7 @@ bool Game::allPlayersAreWaitingOrGameOver()
 bool Game::allPlayersAreGameOver()
 {
 	auto success = true;
-	for (auto &player : players_)
+	for (const auto &player : players_)
 	{
 		success &= player->isGameOver();
 	}
@@ -2394,7 +2375,7 @@ bool Game::allPlayersAreGameOver()
 bool Game::allPlayersAreNotPlaying()
 {
 	auto success = true;
-	for (auto &player : players_)
+	for (const auto &player : players_)
 	{
 		success &= !player->isPlaying();
 	}
@@ -2566,7 +2547,7 @@ void Game::reloadTextures()
 // Actualiza el marcador
 void Game::updateScoreboard()
 {
-	for (auto &player : players_)
+	for (const auto &player : players_)
 	{
 		scoreboard_->setScore(player->getScoreBoardPanel(), player->getScore());
 		scoreboard_->setMult(player->getScoreBoardPanel(), player->getScoreMultiplier());
@@ -2590,7 +2571,7 @@ void Game::pause(bool value)
 }
 
 // Añade una puntuación a la tabla de records
-void Game::addScoreToScoreBoard(std::string name, int score)
+void Game::addScoreToScoreBoard(const std::string &name, int score)
 {
 	const auto entry = (HiScoreEntry){trim(name), score};
 	auto manager = std::make_unique<ManageHiScoreTable>(&options.game.hi_score_table);
@@ -2635,7 +2616,7 @@ void Game::checkPlayersStatusPlaying()
 // Obtiene un jugador a partir de su "id"
 std::shared_ptr<Player> Game::getPlayer(int id)
 {
-	for (auto &player : players_)
+	for (const auto &player : players_)
 	{
 		if (player->getId() == id)
 		{
diff --git a/source/game.h b/source/game.h
index b314066..cd92313 100644
--- a/source/game.h
+++ b/source/game.h
@@ -233,7 +233,7 @@ private:
 	bool saveDemoFile(const std::string &file_path);
 #endif
 	// Crea una formación de enemigos
-	void deployEnemyFormation();
+	void deployBalloonFormation();
 
 	// Aumenta el poder de la fase
 	void increaseStageCurrentPower(int power);
@@ -362,7 +362,7 @@ private:
 	void incTimeStoppedCounter(int value);
 
 	// Actualiza la variable EnemyDeployCounter
-	void updateEnemyDeployCounter();
+	void updateBalloonDeployCounter();
 
 	// Actualiza y comprueba el valor de la variable
 	void updateTimeStoppedCounter();
@@ -431,7 +431,7 @@ private:
 	void checkMusicStatus();
 
 	// Añade una puntuación a la tabla de records
-	void addScoreToScoreBoard(std::string name, int score);
+	void addScoreToScoreBoard(const std::string &name, int score);
 
 	// Saca del estado de GAME OVER al jugador si el otro está activo
 	void checkAndUpdatePlayerStatus(int active_player_index, int inactive_player_index);
diff --git a/source/manage_hiscore_table.cpp b/source/manage_hiscore_table.cpp
index 5b8e4d8..ff1abc0 100644
--- a/source/manage_hiscore_table.cpp
+++ b/source/manage_hiscore_table.cpp
@@ -50,7 +50,7 @@ void ManageHiScoreTable::sort()
 {
     struct
     {
-        bool operator()(HiScoreEntry &a, HiScoreEntry &b) const { return a.score > b.score; }
+        bool operator()(const HiScoreEntry &a, const HiScoreEntry &b) const { return a.score > b.score; }
     } custom_less;
 
     std::sort(table_->begin(), table_->end(), custom_less);
diff --git a/source/notify.cpp b/source/notify.cpp
index 3de069b..f68d51b 100644
--- a/source/notify.cpp
+++ b/source/notify.cpp
@@ -10,7 +10,7 @@
 #include "texture.h" // for Texture
 
 // Constructor
-Notify::Notify(SDL_Renderer *renderer, std::string iconFile, std::string bitmapFile, std::string textFile, std::string soundFile)
+Notify::Notify(SDL_Renderer *renderer, std::string iconFile, std::string bitmapFile, std::string textFile, const std::string &soundFile)
     : renderer(renderer),
       text(std::make_unique<Text>(bitmapFile, textFile, renderer)),
       bgColor(param.notification.color),
diff --git a/source/notify.h b/source/notify.h
index 75d4eb2..89ab780 100644
--- a/source/notify.h
+++ b/source/notify.h
@@ -77,7 +77,7 @@ private:
 
 public:
 	// Constructor
-	Notify(SDL_Renderer *renderer, std::string iconFile, std::string bitmapFile, std::string textFile, std::string soundFile);
+	Notify(SDL_Renderer *renderer, std::string iconFile, std::string bitmapFile, std::string textFile, const std::string &soundFile);
 
 	// Destructor
 	~Notify();
diff --git a/source/options.cpp b/source/options.cpp
index 53194e7..8439203 100644
--- a/source/options.cpp
+++ b/source/options.cpp
@@ -13,7 +13,7 @@
 Options options;
 
 // Declaraciones
-bool setOptions(std::string var, const std::string &value);
+bool setOptions(const std::string &var, const std::string &value);
 
 // Inicializa las opciones del programa
 void initOptions()
@@ -244,7 +244,7 @@ bool saveOptionsFile(std::string file_path)
 }
 
 // Asigna variables a partir de dos cadenas
-bool setOptions(std::string var, const std::string &value)
+bool setOptions(const std::string &var, const std::string &value)
 {
 	// Indicador de éxito en la asignación
 	auto success = true;
diff --git a/source/param.cpp b/source/param.cpp
index 6d850ee..59c6165 100644
--- a/source/param.cpp
+++ b/source/param.cpp
@@ -1,7 +1,10 @@
 #include "param.h"
 #include <fstream>	// for char_traits, basic_ostream, basic_ifstream, basi...
 #include <iostream> // for cout
-#include "utils.h"	// for Param, ParamGame, Zone, ParamBalloon
+#include <sstream>
+#include <string>
+#include <stdexcept>
+#include "utils.h" // for Param, ParamGame, Zone, ParamBalloon
 
 Param param;
 
@@ -40,7 +43,7 @@ void initParam()
 	param.title.title_c_c_position = 11;
 
 	// BACKGROUND
-	param.background.attenuate_color = {255, 255, 255};
+	param.background.attenuate_color = (Color){255, 255, 255};
 	param.background.attenuate_alpha = 32;
 
 	// BALLOONS
@@ -52,10 +55,18 @@ void initParam()
 	param.balloon_3.grav = 0.10f;
 	param.balloon_4.vel = 4.95f;
 	param.balloon_4.grav = 0.10f;
+
+	// NOTIFICATION
+	param.notification.pos_v = NotifyPosition::TOP;
+	param.notification.pos_h = NotifyPosition::LEFT;
+	param.notification.sound = false;
+	param.notification.color.r = 48;
+	param.notification.color.g = 48;
+	param.notification.color.b = 48;
 }
 
 // Establece valores para los parametros a partir de un fichero de texto
-void loadParamsFromFile(std::string file_path)
+/*void loadParamsFromFile(std::string file_path)
 {
 	// Pone valores por defecto a las variables
 	initParam();
@@ -80,8 +91,15 @@ void loadParamsFromFile(std::string file_path)
 			param1.clear();
 			param2.clear();
 
-			// Elimina los comentarios
-			line = line.substr(0, line.find("#"));
+			// Elimina los comentarios al final de una linea
+			{
+				// line = line.substr(0, line.find("#"));
+				auto pos = line.find("#");
+				if (pos != std::string::npos)
+				{
+					line.resize(pos);
+				}
+			}
 
 			// Ignora los espacios en blanco
 			int pos = 0;
@@ -148,6 +166,50 @@ void loadParamsFromFile(std::string file_path)
 		std::cout << "Failed to load file: " << file_path << std::endl;
 #endif
 
+	precalculateZones();
+}*/
+void loadParamsFromFile(const std::string &file_path)
+{
+	// Inicializa los parámetros con valores por defecto
+	initParam();
+
+	// Abre el archivo
+	std::ifstream file(file_path);
+	if (!file.is_open())
+	{
+#ifdef VERBOSE
+		std::cerr << "Error: No se pudo abrir el archivo " << file_path << std::endl;
+#endif
+		throw std::runtime_error("No se pudo abrir el archivo: " + file_path);
+	}
+
+#ifdef VERBOSE
+	const std::string file_name = file_path.substr(file_path.find_last_of("\\/") + 1);
+	std::cout << "Reading file: " << file_name << std::endl;
+#endif
+
+	std::string line, param1, param2;
+	while (std::getline(file, line))
+	{
+		// Elimina comentarios
+		auto comment_pos = line.find('#');
+		if (comment_pos != std::string::npos)
+		{
+			line = line.substr(0, comment_pos);
+		}
+
+		// Usa un stream para separar palabras
+		std::istringstream iss(line);
+		if (iss >> param1 >> param2)
+		{
+			setParams(param1, param2);
+		}
+	}
+
+	// Cierra el archivo
+	file.close();
+
+	// Realiza cálculos adicionales después de cargar los parámetros
 	precalculateZones();
 }
 
diff --git a/source/param.h b/source/param.h
index f0f9530..8e688a5 100644
--- a/source/param.h
+++ b/source/param.h
@@ -6,4 +6,4 @@ struct Param;
 extern Param param;
 
 // Establece valores para los parametros a partir de un fichero de texto
-void loadParamsFromFile(std::string file_path);
\ No newline at end of file
+void loadParamsFromFile(const std::string &file_path);
\ No newline at end of file
diff --git a/source/player.cpp b/source/player.cpp
index 7f10f9b..8ae99ef 100644
--- a/source/player.cpp
+++ b/source/player.cpp
@@ -12,30 +12,29 @@
 
 // Constructor
 Player::Player(int id, float x, int y, bool demo, SDL_Rect *play_area, std::vector<std::shared_ptr<Texture>> texture, std::vector<std::vector<std::string> *> animations)
+	: player_sprite_(std::make_unique<AnimatedSprite>(texture[0], "", animations[0])),
+	  power_sprite_(std::make_unique<AnimatedSprite>(texture[1], "", animations[1])),
+	  enter_name_(std::make_unique<EnterName>()),
+	  play_area_(play_area),
+	  id_(id),
+	  pos_x_(x),
+	  pos_y_(y),
+	  default_pos_x_(x),
+	  default_pos_y_(y),
+	  status_playing_(PlayerStatus::WAITING),
+	  scoreboard_panel_(0),
+	  name_(std::string()),
+	  controller_index_(0),
+	  demo_(demo)
 {
 	// Reserva memoria para los objetos
-	player_sprite_ = std::make_unique<AnimatedSprite>(texture[0], "", animations[0]);
-	power_sprite_ = std::make_unique<AnimatedSprite>(texture[1], "", animations[1]);
 	power_sprite_->getTexture()->setAlpha(224);
-	enter_name_ = std::make_unique<EnterName>();
-
-	// Rectangulo con la zona de juego
-	play_area_ = play_area;
-
-	// Establece la posición inicial del jugador
-	default_pos_x_ = pos_x_ = x;
-	default_pos_y_ = pos_y_ = y;
 
 	// Establece los offsets para el sprite de PowerUp
 	power_up_desp_x_ = (power_sprite_->getWidth() - player_sprite_->getWidth()) / 2;
 	power_sprite_->setPosY(y - (power_sprite_->getHeight() - player_sprite_->getHeight()));
 
 	// Inicializa variables
-	id_ = id;
-	demo_ = demo;
-	status_playing_ = PlayerStatus::WAITING;
-	scoreboard_panel_ = 0;
-	name_.clear();
 	setRecordName(enter_name_->getName());
 	init();
 }
@@ -237,21 +236,13 @@ void Player::render()
 // Establece el estado del jugador cuando camina
 void Player::setWalkingStatus(PlayerStatus status)
 {
-	// Si cambiamos de estado, reiniciamos la animación
-	if (status_walking_ != status)
-	{
-		status_walking_ = status;
-	}
+	status_walking_ = status;
 }
 
 // Establece el estado del jugador cuando dispara
 void Player::setFiringStatus(PlayerStatus status)
 {
-	// Si cambiamos de estado, reiniciamos la animación
-	if (status_firing_ != status)
-	{
-		status_firing_ = status;
-	}
+	status_firing_ = status;
 }
 
 // Establece la animación correspondiente al estado
@@ -694,7 +685,7 @@ void Player::shiftColliders()
 }
 
 // Pone las texturas del jugador
-void Player::setPlayerTextures(std::vector<std::shared_ptr<Texture>> texture)
+void Player::setPlayerTextures(const std::vector<std::shared_ptr<Texture>> &texture)
 {
 	player_sprite_->setTexture(texture[0]);
 	power_sprite_->setTexture(texture[1]);
@@ -736,7 +727,7 @@ int Player::getScoreBoardPanel() const
 void Player::decContinueCounter()
 {
 	continue_ticks_ = SDL_GetTicks();
-	continue_counter_--;
+	--continue_counter_;
 	if (continue_counter_ < 0)
 	{
 		setStatusPlaying(PlayerStatus::GAME_OVER);
@@ -744,13 +735,13 @@ void Player::decContinueCounter()
 }
 
 // Establece el nombre del jugador
-void Player::setName(std::string name)
+void Player::setName(const std::string &name)
 {
 	name_ = name;
 }
 
 // Establece el nombre del jugador para la tabla de mejores puntuaciones
-void Player::setRecordName(std::string record_name)
+void Player::setRecordName(const std::string &record_name)
 {
 	record_name_ = record_name.substr(0, 8);
 }
diff --git a/source/player.h b/source/player.h
index 45adb4f..8047556 100644
--- a/source/player.h
+++ b/source/player.h
@@ -118,7 +118,7 @@ public:
 	void render();
 
 	// Pone las texturas del jugador
-	void setPlayerTextures(std::vector<std::shared_ptr<Texture>> texture);
+	void setPlayerTextures(const std::vector<std::shared_ptr<Texture>> &texture);
 
 	// Actua en consecuencia de la entrada recibida
 	void setInput(InputType input);
@@ -271,10 +271,10 @@ public:
 	void decContinueCounter();
 
 	// Establece el nombre del jugador
-	void setName(std::string name);
+	void setName(const std::string &name);
 
 	// Establece el nombre del jugador para la tabla de mejores puntuaciones
-	void setRecordName(std::string record_name);
+	void setRecordName(const std::string &record_name);
 
 	// Obtiene el nombre del jugador
 	std::string getName() const;
diff --git a/source/scoreboard.cpp b/source/scoreboard.cpp
index 668d509..7bdd94c 100644
--- a/source/scoreboard.cpp
+++ b/source/scoreboard.cpp
@@ -34,13 +34,21 @@ Scoreboard *Scoreboard::get()
 
 // Constructor
 Scoreboard::Scoreboard(SDL_Renderer *renderer)
-	: renderer_(renderer)
+	: renderer_(renderer),
+	  
+	  game_power_meter_texture_(std::make_shared<Texture>(renderer, Asset::get()->get("game_power_meter.png"))),
+	  power_meter_sprite_(std::make_unique<Sprite>(game_power_meter_texture_)),
+	  text_scoreboard_(std::make_unique<Text>(Asset::get()->get("8bithud.png"), Asset::get()->get("8bithud.txt"), renderer)),
+	  
+	  stage_(1),
+	  hi_score_(0),
+	  power_(0),
+	  hi_score_name_(std::string()),
+	  color_({0, 0, 0}),
+	  rect_({0, 0, 320, 40}),
+	  ticks_(SDL_GetTicks()),
+	  counter_(0)
 {
-	// Inicializa punteros
-	game_power_meter_texture_ = nullptr;
-	power_meter_sprite_ = nullptr;
-	text_scoreboard_ = nullptr;
-
 	// Inicializa variables
 	for (int i = 0; i < SCOREBOARD_MAX_PANELS; ++i)
 	{
@@ -51,25 +59,14 @@ Scoreboard::Scoreboard(SDL_Renderer *renderer)
 		mult_[i] = 0;
 		continue_counter_[i] = 0;
 	}
-	stage_ = 1;
-	hi_score_ = 0;
-	power_ = 0;
-	hi_score_name_.clear();
-	color_ = {0, 0, 0};
-	rect_ = {0, 0, 320, 40};
+
 	panel_[SCOREBOARD_LEFT_PANEL].mode = ScoreboardMode::SCORE;
 	panel_[SCOREBOARD_RIGHT_PANEL].mode = ScoreboardMode::SCORE;
 	panel_[SCOREBOARD_CENTER_PANEL].mode = ScoreboardMode::STAGE_INFO;
-	ticks_ = SDL_GetTicks();
-	counter_ = 0;
 
 	// Recalcula las anclas de los elementos
 	recalculateAnchors();
-
-	// Crea objetos
-	game_power_meter_texture_ = std::make_shared<Texture>(renderer_, Asset::get()->get("game_power_meter.png"));
-	power_meter_sprite_ = std::make_unique<Sprite>(slot4_2_.x - 20, slot4_2_.y, 40, 7, game_power_meter_texture_);
-	text_scoreboard_ = std::make_unique<Text>(Asset::get()->get("8bithud.png"), Asset::get()->get("8bithud.txt"), renderer_);
+	power_meter_sprite_->setPos({slot4_2_.x - 20, slot4_2_.y, 40, 7});
 
 	// Crea la textura de fondo
 	background_ = nullptr;
@@ -130,13 +127,13 @@ void Scoreboard::render()
 }
 
 // Establece el valor de la variable
-void Scoreboard::setName(int panel_, std::string name_)
+void Scoreboard::setName(int panel_, const std::string &name_)
 {
 	this->name_[panel_] = name_;
 }
 
 // Establece el valor de la variable
-void Scoreboard::setRecordName(int panel_, std::string record_name_)
+void Scoreboard::setRecordName(int panel_, const std::string &record_name_)
 {
 	this->record_name_[panel_] = record_name_;
 }
@@ -184,7 +181,7 @@ void Scoreboard::setPower(float power_)
 }
 
 // Establece el valor de la variable
-void Scoreboard::setHiScoreName(std::string name_)
+void Scoreboard::setHiScoreName(const std::string &name_)
 {
 	hi_score_name_ = name_;
 }
@@ -323,7 +320,7 @@ void Scoreboard::fillPanelTextures()
 
 			// ENTER NAME
 			text_scoreboard_->writeCentered(slot4_3_.x, slot4_3_.y, lang::getText(106));
-			SDL_Rect rect_ = {enter_name_pos_.x, enter_name_pos_.y, 5, 7};
+			SDL_Rect rect = {enter_name_pos_.x, enter_name_pos_.y, 5, 7};
 			SDL_SetRenderDrawColor(renderer_, 0xFF, 0xFF, 0xEB, 255);
 			for (int j = 0; j < (int)record_name_[i].size(); ++j)
 			{
@@ -331,16 +328,16 @@ void Scoreboard::fillPanelTextures()
 				{ // La letra seleccionada se pinta de forma intermitente
 					if (counter_ % 3 > 0)
 					{
-						SDL_RenderDrawLine(renderer_, rect_.x, rect_.y + rect_.h, rect_.x + rect_.w, rect_.y + rect_.h);
-						text_scoreboard_->write(rect_.x, rect_.y, record_name_[i].substr(j, 1));
+						SDL_RenderDrawLine(renderer_, rect.x, rect.y + rect.h, rect.x + rect.w, rect.y + rect.h);
+						text_scoreboard_->write(rect.x, rect.y, record_name_[i].substr(j, 1));
 					}
 				}
 				else
 				{
-					SDL_RenderDrawLine(renderer_, rect_.x, rect_.y + rect_.h, rect_.x + rect_.w, rect_.y + rect_.h);
-					text_scoreboard_->write(rect_.x, rect_.y, record_name_[i].substr(j, 1));
+					SDL_RenderDrawLine(renderer_, rect.x, rect.y + rect.h, rect.x + rect.w, rect.y + rect.h);
+					text_scoreboard_->write(rect.x, rect.y, record_name_[i].substr(j, 1));
 				}
-				rect_.x += 7;
+				rect.x += 7;
 			}
 			break;
 		}
diff --git a/source/scoreboard.h b/source/scoreboard.h
index 1809ed1..1500388 100644
--- a/source/scoreboard.h
+++ b/source/scoreboard.h
@@ -50,9 +50,9 @@ private:
 
 	std::shared_ptr<Texture> game_power_meter_texture_; // Textura con el marcador de poder de la fase
 	std::unique_ptr<Sprite> power_meter_sprite_;		// Sprite para el medidor de poder de la fase
-	std::unique_ptr<Text> text_scoreboard_;			// Fuente para el marcador del juego
+	std::unique_ptr<Text> text_scoreboard_;				// Fuente para el marcador del juego
 
-	SDL_Texture *background_;				 // Textura para dibujar el marcador
+	SDL_Texture *background_;				   // Textura para dibujar el marcador
 	std::vector<SDL_Texture *> panel_texture_; // Texturas para dibujar cada panel
 
 	// Variables
@@ -125,10 +125,10 @@ public:
 	void render();
 
 	// Establece el valor de la variable
-	void setName(int panel, std::string name);
+	void setName(int panel, const std::string &name);
 
 	// Establece el valor de la variable
-	void setRecordName(int panel, std::string record_name);
+	void setRecordName(int panel, const std::string &record_name);
 
 	// Establece el valor de la variable
 	void setSelectorPos(int panel, int pos);
@@ -152,7 +152,7 @@ public:
 	void setPower(float power);
 
 	// Establece el valor de la variable
-	void setHiScoreName(std::string name);
+	void setHiScoreName(const std::string &name);
 
 	// Establece el valor de la variable
 	void setColor(Color color);
diff --git a/source/screen.cpp b/source/screen.cpp
index 926c8cc..c7e2026 100644
--- a/source/screen.cpp
+++ b/source/screen.cpp
@@ -44,12 +44,27 @@ Screen *Screen::get()
 
 // Constructor
 Screen::Screen(SDL_Window *window, SDL_Renderer *renderer)
-    : window_(window), renderer_(renderer)
+    : window_(window),
+      renderer_(renderer),
+
+      notify_(std::make_unique<Notify>(renderer_, std::string(), Asset::get()->get("8bithud.png"), Asset::get()->get("8bithud.txt"), Asset::get()->get("notify.wav"))),
+      game_canvas_(SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, param.game.width, param.game.height)),
+      shader_canvas_(SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, param.game.width, param.game.height)),
+
+      src_rect_({0, 0, param.game.width, param.game.height}),
+      dst_rect_({0, 0, param.game.width, param.game.height}),
+      border_color_({0x00, 0x00, 0x00}),
+      attenuate_effect_(false),
+      fps_ticks_(0),
+      fps_counter_(0),
+      fps_(0),
+#ifdef DEBUG
+      show_info_(true)
+#else
+      show_info_(false)
+#endif
 {
     // Inicializa variables
-    src_rect_ = {0, 0, param.game.width, param.game.height};
-    dst_rect_ = {0, 0, param.game.width, param.game.height};
-    border_color_ = {0, 0, 0};
     flash_effect_.enabled = false;
     flash_effect_.counter = 0;
     flash_effect_.lenght = 0;
@@ -62,29 +77,10 @@ Screen::Screen(SDL_Window *window, SDL_Renderer *renderer)
     shake_effect_.remaining = 0;
     shake_effect_.originalPos = 0;
     shake_effect_.originalWidth = param.game.width;
-    attenuate_effect_ = false;
-    fps_ticks_ = 0;
-    fps_counter_ = 0;
-    fps_ = 0;
-#ifdef DEBUG
-    show_info_ = true;
-#else
-    show_info_ = false;
-#endif
     SDL_DisplayMode DM;
     SDL_GetCurrentDisplayMode(0, &DM);
     info_resolution_ = std::to_string(DM.w) + " X " + std::to_string(DM.h) + " AT " + std::to_string(DM.refresh_rate) + " HZ";
 
-    // Crea los objetos
-    notify_ = std::make_unique<Notify>(renderer_, "", Asset::get()->get("8bithud.png"), Asset::get()->get("8bithud.txt"), Asset::get()->get("notify.wav"));
-
-    // Define el color del borde para el modo de pantalla completa
-    border_color_ = {0x00, 0x00, 0x00};
-
-    // Crea las textura donde se dibujan los graficos del juego
-    game_canvas_ = SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, param.game.width, param.game.height);
-    shader_canvas_ = SDL_CreateTexture(renderer_, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, param.game.width, param.game.height);
-
     // Establece el modo de video
     setVideoMode(options.video.mode);
 
@@ -183,9 +179,10 @@ void Screen::blit()
 // Establece el modo de video
 void Screen::setVideoMode(ScreenVideoMode videoMode)
 {
-    options.video.mode = videoMode;
 #ifdef ARCADE
     options.video.mode = ScreenVideoMode::WINDOW;
+#else
+    options.video.mode = videoMode;
 #endif
 
     switch (options.video.mode)
@@ -455,7 +452,7 @@ void Screen::attenuate(bool value)
 }
 
 // Muestra una notificación de texto por pantalla;
-void Screen::showNotification(std::string text1, std::string text2, int icon)
+void Screen::showNotification(const std::string &text1, const std::string &text2, int icon)
 {
     notify_->showText(text1, text2, icon);
 }
diff --git a/source/screen.h b/source/screen.h
index 0749648..6379421 100644
--- a/source/screen.h
+++ b/source/screen.h
@@ -152,7 +152,7 @@ public:
 	void attenuate(bool value);
 
 	// Muestra una notificación de texto por pantalla;
-	void showNotification(std::string text1 = std::string(), std::string text2 = std::string(), int icon = -1);
+	void showNotification(const std::string &text1 = std::string(), const std::string &text2 = std::string(), int icon = -1);
 
 	// Indica si hay alguna notificación activa en pantalla
 	bool notificationsAreActive() const;
diff --git a/source/text.cpp b/source/text.cpp
index e28c40a..af93bcf 100644
--- a/source/text.cpp
+++ b/source/text.cpp
@@ -21,7 +21,9 @@ TextFile LoadTextFile(std::string file_path)
 	}
 
 	// Abre el fichero para leer los valores
+#ifdef VERBOSE
 	const std::string file_name = file_path.substr(file_path.find_last_of("\\/") + 1).c_str();
+#endif
 	std::ifstream file(file_path);
 
 	if (file.is_open() && file.good())
@@ -55,7 +57,7 @@ TextFile LoadTextFile(std::string file_path)
 
 // Cierra el fichero
 #ifdef VERBOSE
-		std::cout << "Text loaded: " << file_name.c_str() << std::endl;
+		std::cout << "Text loaded: " << file_name << std::endl;
 #endif
 		file.close();
 	}
@@ -64,7 +66,7 @@ TextFile LoadTextFile(std::string file_path)
 	else
 	{
 #ifdef VERBOSE
-		std::cout << "Warning: Unable to open " << file_name.c_str() << " file" << std::endl;
+		std::cout << "Warning: Unable to open " << file_name << " file" << std::endl;
 #endif
 	}
 
@@ -146,7 +148,7 @@ Text::Text(TextFile *text_file, std::shared_ptr<Texture> texture)
 }
 
 // Escribe texto en pantalla
-void Text::write(int x, int y, std::string text, int kerning, int lenght)
+void Text::write(int x, int y, const std::string &text, int kerning, int lenght)
 {
 	auto shift = 0;
 
@@ -169,7 +171,7 @@ void Text::write(int x, int y, std::string text, int kerning, int lenght)
 }
 
 // Escribe el texto con colores
-void Text::writeColored(int x, int y, std::string text, Color color, int kerning, int lenght)
+void Text::writeColored(int x, int y, const std::string &text, Color color, int kerning, int lenght)
 {
 	sprite_->getTexture()->setColor(color.r, color.g, color.b);
 	write(x, y, text, kerning, lenght);
@@ -177,7 +179,7 @@ void Text::writeColored(int x, int y, std::string text, Color color, int kerning
 }
 
 // Escribe el texto con sombra
-void Text::writeShadowed(int x, int y, std::string text, Color color, Uint8 shadow_distance, int kerning, int lenght)
+void Text::writeShadowed(int x, int y, const std::string &text, Color color, Uint8 shadow_distance, int kerning, int lenght)
 {
 	sprite_->getTexture()->setColor(color.r, color.g, color.b);
 	write(x + shadow_distance, y + shadow_distance, text, kerning, lenght);
@@ -186,14 +188,14 @@ void Text::writeShadowed(int x, int y, std::string text, Color color, Uint8 shad
 }
 
 // Escribe el texto centrado en un punto x
-void Text::writeCentered(int x, int y, std::string text, int kerning, int lenght)
+void Text::writeCentered(int x, int y, const std::string &text, int kerning, int lenght)
 {
 	x -= (Text::lenght(text, kerning) / 2);
 	write(x, y, text, kerning, lenght);
 }
 
 // Escribe texto con extras
-void Text::writeDX(Uint8 flags, int x, int y, std::string text, int kerning, Color textColor, Uint8 shadow_distance, Color shadow_color, int lenght)
+void Text::writeDX(Uint8 flags, int x, int y, const std::string &text, int kerning, Color textColor, Uint8 shadow_distance, Color shadow_color, int lenght)
 {
 	const auto centered = ((flags & TEXT_CENTER) == TEXT_CENTER);
 	const auto shadowed = ((flags & TEXT_SHADOW) == TEXT_SHADOW);
@@ -235,7 +237,7 @@ void Text::writeDX(Uint8 flags, int x, int y, std::string text, int kerning, Col
 }
 
 // Obtiene la longitud en pixels de una cadena
-int Text::lenght(std::string text, int kerning) const
+int Text::lenght(const std::string &text, int kerning) const
 {
 	auto shift = 0;
 
@@ -267,7 +269,7 @@ void Text::setFixedWidth(bool value)
 }
 
 // Carga una paleta de colores para el texto
-void Text::addPalette(std::string path)
+void Text::addPalette(const std::string &path)
 {
 	texture_->addPalette(path);
 }
diff --git a/source/text.h b/source/text.h
index 240514b..ae68315 100644
--- a/source/text.h
+++ b/source/text.h
@@ -52,22 +52,22 @@ public:
 	~Text() = default;
 
 	// Escribe el texto en pantalla
-	void write(int x, int y, std::string text, int kerning = 1, int lenght = -1);
+	void write(int x, int y, const std::string &text, int kerning = 1, int lenght = -1);
 
 	// Escribe el texto con colores
-	void writeColored(int x, int y, std::string text, Color color, int kerning = 1, int lenght = -1);
+	void writeColored(int x, int y, const std::string &text, Color color, int kerning = 1, int lenght = -1);
 
 	// Escribe el texto con sombra
-	void writeShadowed(int x, int y, std::string text, Color color, Uint8 shadow_distance = 1, int kerning = 1, int lenght = -1);
+	void writeShadowed(int x, int y, const std::string &text, Color color, Uint8 shadow_distance = 1, int kerning = 1, int lenght = -1);
 
 	// Escribe el texto centrado en un punto x
-	void writeCentered(int x, int y, std::string text, int kerning = 1, int lenght = -1);
+	void writeCentered(int x, int y, const std::string &text, int kerning = 1, int lenght = -1);
 
 	// Escribe texto con extras
-	void writeDX(Uint8 flags, int x, int y, std::string text, int kerning = 1, Color textColor = {255, 255, 255}, Uint8 shadow_distance = 1, Color shadow_color = {0, 0, 0}, int lenght = -1);
+	void writeDX(Uint8 flags, int x, int y, const std::string &text, int kerning = 1, Color textColor = {255, 255, 255}, Uint8 shadow_distance = 1, Color shadow_color = {0, 0, 0}, int lenght = -1);
 
 	// Obtiene la longitud en pixels de una cadena
-	int lenght(std::string text, int kerning = 1) const;
+	int lenght(const std::string &text, int kerning = 1) const;
 
 	// Devuelve el valor de la variable
 	int getCharacterSize() const;
@@ -79,7 +79,7 @@ public:
 	void setFixedWidth(bool value);
 
 	// Carga una paleta de colores para el texto
-	void addPalette(std::string path);
+	void addPalette(const std::string &path);
 
 	// Establece una paleta de colores para el texto
 	void setPalette(int index);
diff --git a/source/texture.cpp b/source/texture.cpp
index 1e49bea..a661bc5 100644
--- a/source/texture.cpp
+++ b/source/texture.cpp
@@ -11,7 +11,7 @@
 #include "stb_image.h" // for stbi_failure_reason, stbi_image_free
 
 // Constructor
-Texture::Texture(SDL_Renderer *renderer, std::string path)
+Texture::Texture(SDL_Renderer *renderer, const std::string &path)
 	: renderer_(renderer), path_(path)
 {
 	// Inicializa
@@ -37,8 +37,8 @@ Texture::Texture(SDL_Renderer *renderer, std::string path)
 		// .gif
 		else if (extension == "gif")
 		{
-			surface_ = loadSurface(path_.c_str());
-			addPalette(path_.c_str());
+			surface_ = loadSurface(path_);
+			addPalette(path_);
 			setPaletteColor(0, 0, 0x00000000);
 			createBlank(width_, height_, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_STREAMING);
 			SDL_SetTextureBlendMode(texture_, SDL_BLENDMODE_BLEND);
@@ -54,13 +54,13 @@ Texture::~Texture()
 }
 
 // Carga una imagen desde un fichero
-bool Texture::loadFromFile(std::string path)
+bool Texture::loadFromFile(const std::string &path)
 {
 	const std::string file_name = path.substr(path.find_last_of("\\/") + 1);
 	int req_format = STBI_rgb_alpha;
 	int width, height, orig_format;
 	unsigned char *data = stbi_load(path.c_str(), &width, &height, &orig_format, req_format);
-	if (data == nullptr)
+	if (!data)
 	{
 #ifdef VERBOSE
 		std::cout << "Loading image failed: " << stbi_failure_reason() << std::endl;
@@ -70,19 +70,19 @@ bool Texture::loadFromFile(std::string path)
 	else
 	{
 #ifdef VERBOSE
-		std::cout << "Image loaded: " << file_name.c_str() << std::endl;
+		std::cout << "Image loaded: " << file_name << std::endl;
 #endif
 	}
 
 	int depth, pitch;
 	Uint32 pixel_format;
-	if (req_format == STBI_rgb)
+	/*if (req_format == STBI_rgb)
 	{
 		depth = 24;
 		pitch = 3 * width; // 3 bytes por pixel * pixels por linea
 		pixel_format = SDL_PIXELFORMAT_RGB24;
 	}
-	else
+	else*/
 	{ // STBI_rgb_alpha (RGBA)
 		depth = 32;
 		pitch = 4 * width;
@@ -96,11 +96,11 @@ bool Texture::loadFromFile(std::string path)
 	SDL_Texture *newTexture = nullptr;
 
 	// Carga la imagen desde una ruta específica
-	SDL_Surface *loadedSurface = SDL_CreateRGBSurfaceWithFormatFrom((void *)data, width, height, depth, pitch, pixel_format);
+	auto loadedSurface = SDL_CreateRGBSurfaceWithFormatFrom(static_cast<void*>(data), width, height, depth, pitch, pixel_format);
 	if (loadedSurface == nullptr)
 	{
 #ifdef VERBOSE
-		std::cout << "Unable to load image " << path.c_str() << std::endl;
+		std::cout << "Unable to load image " << path << std::endl;
 #endif
 	}
 	else
@@ -110,7 +110,7 @@ bool Texture::loadFromFile(std::string path)
 		if (newTexture == nullptr)
 		{
 #ifdef VERBOSE
-			std::cout << "Unable to create texture from " << path.c_str() << "! SDL Error: " << SDL_GetError() << std::endl;
+			std::cout << "Unable to create texture from " << path << "! SDL Error: " << SDL_GetError() << std::endl;
 #endif
 		}
 		else
@@ -241,10 +241,10 @@ SDL_Texture *Texture::getSDLTexture()
 // Crea una nueva surface
 Surface Texture::newSurface(int w, int h)
 {
-	Surface surf = (Surface)malloc(sizeof(surface_s));
+	Surface surf = static_cast<Surface>(malloc(sizeof(surface_s)));
 	surf->w = w;
 	surf->h = h;
-	surf->data = (Uint8 *)malloc(w * h);
+	surf->data = static_cast<Uint8 *>(malloc(w * h));
 	return surf;
 }
 
@@ -265,29 +265,29 @@ void Texture::deleteSurface(Surface surface)
 }
 
 // Crea una surface desde un fichero .gif
-Surface Texture::loadSurface(const char *file_name)
+Surface Texture::loadSurface(const std::string &file_name)
 {
-	FILE *f = fopen(file_name, "rb");
+	FILE *f = fopen(file_name.c_str(), "rb");
 	if (!f)
 	{
-		return NULL;
+		return nullptr;
 	}
 
 	fseek(f, 0, SEEK_END);
 	long size = ftell(f);
 	fseek(f, 0, SEEK_SET);
-	Uint8 *buffer = (Uint8 *)malloc(size);
+	Uint8 *buffer = static_cast<Uint8 *>(malloc(size));
 	fread(buffer, size, 1, f);
 	fclose(f);
 
 	Uint16 w, h;
 	Uint8 *pixels = LoadGif(buffer, &w, &h);
-	if (pixels == NULL)
+	if (pixels == nullptr)
 	{
-		return NULL;
+		return nullptr;
 	}
 
-	Surface surface = (Surface)malloc(sizeof(surface_s));
+	Surface surface = static_cast<Surface>(malloc(sizeof(surface_s)));
 	surface->w = w;
 	surface->h = h;
 	surface->data = pixels;
@@ -312,7 +312,7 @@ void Texture::flipSurface()
 	// Vuelca los datos
 	Uint32 *pixels;
 	int pitch;
-	SDL_LockTexture(texture_, nullptr, (void **)&pixels, &pitch);
+	SDL_LockTexture(texture_, nullptr, reinterpret_cast<void**>(&pixels), &pitch);
 	for (int i = 0; i < width_ * height_; ++i)
 	{
 		pixels[i] = palettes_[paletteIndex_][surface_->data[i]];
@@ -327,11 +327,11 @@ void Texture::setPaletteColor(int palette, int index, Uint32 color)
 }
 
 // Carga una paleta desde un fichero
-std::vector<Uint32> Texture::loadPal(const char *file_name)
+std::vector<Uint32> Texture::loadPal(const std::string &file_name)
 {
 	std::vector<Uint32> palette;
 
-	FILE *f = fopen(file_name, "rb");
+	FILE *f = fopen(file_name.c_str(), "rb");
 	if (!f)
 	{
 		return palette;
@@ -340,12 +340,12 @@ std::vector<Uint32> Texture::loadPal(const char *file_name)
 	fseek(f, 0, SEEK_END);
 	long size = ftell(f);
 	fseek(f, 0, SEEK_SET);
-	Uint8 *buffer = (Uint8 *)malloc(size);
+	Uint8 *buffer = static_cast<Uint8 *>(malloc(size));
 	fread(buffer, size, 1, f);
 	fclose(f);
 
-	Uint32 *pal = LoadPalette(buffer);
-	if (pal == nullptr)
+	auto pal = LoadPalette(buffer);
+	if (!pal)
 	{
 		return palette;
 	}
diff --git a/source/texture.h b/source/texture.h
index c533ab0..361bcee 100644
--- a/source/texture.h
+++ b/source/texture.h
@@ -39,23 +39,23 @@ private:
     void deleteSurface(Surface surface);
 
     // Crea una surface desde un fichero .gif
-    Surface loadSurface(const char *file_name);
+    Surface loadSurface(const std::string &file_name);
 
     // Vuelca la surface en la textura
     void flipSurface(); 
 
     // Carga una paleta desde un fichero
-    std::vector<Uint32> loadPal(const char *file_name);
+    std::vector<Uint32> loadPal(const std::string &file_name);
 
 public:
     // Constructor
-    explicit Texture(SDL_Renderer *renderer, std::string path = std::string());
+    explicit Texture(SDL_Renderer *renderer, const std::string &path = std::string());
 
     // Destructor
     ~Texture();
 
     // Carga una imagen desde un fichero
-    bool loadFromFile(std::string path);
+    bool loadFromFile(const std::string &path);
 
     // Crea una textura en blanco
     bool createBlank(int width, int height, SDL_PixelFormatEnum format = SDL_PIXELFORMAT_RGBA8888, SDL_TextureAccess = SDL_TEXTUREACCESS_STREAMING);
diff --git a/source/title.cpp b/source/title.cpp
index 5a170b9..3ddc578 100644
--- a/source/title.cpp
+++ b/source/title.cpp
@@ -315,9 +315,9 @@ void Title::resetCounter()
 // Intercambia la asignación de mandos a los jugadores
 void Title::swapControllers()
 {
-	const int num_controllers_ = input_->getNumControllers();
+	const auto num_controllers = input_->getNumControllers();
 
-	if (num_controllers_ == 0)
+	if (num_controllers == 0)
 	{
 		return;
 	}
diff --git a/source/utils.cpp b/source/utils.cpp
index e8fdc10..01394ab 100644
--- a/source/utils.cpp
+++ b/source/utils.cpp
@@ -29,210 +29,112 @@ double distanceSquared(int x1, int y1, int x2, int y2)
 }
 
 // Detector de colisiones entre dos circulos
-bool checkCollision(Circle &a, Circle &b)
+bool checkCollision(const Circle &a, const Circle &b)
 {
     // Calcula el radio total al cuadrado
-    int total_radius_squared = a.r + b.r;
-    total_radius_squared = total_radius_squared * total_radius_squared;
+    int total_radius_squared = (a.r + b.r) * (a.r + b.r);
 
-    // Si la distancia entre el centro de los circulos es inferior a la suma de sus radios
-    if (distanceSquared(a.x, a.y, b.x, b.y) < (total_radius_squared))
-    {
-        // Los circulos han colisionado
-        return true;
-    }
-
-    // En caso contrario
-    return false;
+    // Comprueba si la distancia entre los centros de los círculos es inferior a la suma de sus radios
+    return distanceSquared(a.x, a.y, b.x, b.y) < total_radius_squared;
 }
 
 // Detector de colisiones entre un circulo y un rectangulo
-bool checkCollision(Circle &a, SDL_Rect &b)
+bool checkCollision(const Circle &a, const SDL_Rect &b)
 {
-    // Closest point on collision box
-    int cX, cY;
+    // Encuentra el punto más cercano en el rectángulo
+    int cX = std::clamp(a.x, b.x, b.x + b.w);
+    int cY = std::clamp(a.y, b.y, b.y + b.h);
 
-    // Find closest x offset
-    if (a.x < b.x)
-    {
-        cX = b.x;
-    }
-    else if (a.x > b.x + b.w)
-    {
-        cX = b.x + b.w;
-    }
-    else
-    {
-        cX = a.x;
-    }
-
-    // Find closest y offset
-    if (a.y < b.y)
-    {
-        cY = b.y;
-    }
-    else if (a.y > b.y + b.h)
-    {
-        cY = b.y + b.h;
-    }
-    else
-    {
-        cY = a.y;
-    }
-
-    // If the closest point is inside the Circle
-    if (distanceSquared(a.x, a.y, cX, cY) < a.r * a.r)
-    {
-        // This box and the Circle have collided
-        return true;
-    }
-
-    // If the shapes have not collided
-    return false;
+    // Si el punto más cercano está dentro del círculo
+    return distanceSquared(a.x, a.y, cX, cY) < a.r * a.r;
 }
 
 // Detector de colisiones entre dos rectangulos
-bool checkCollision(SDL_Rect &a, SDL_Rect &b)
+bool checkCollision(const SDL_Rect &a, const SDL_Rect &b)
 {
-    // Calcula las caras del rectangulo a
-    const int leftA = a.x;
-    const int rightA = a.x + a.w;
-    const int topA = a.y;
-    const int bottomA = a.y + a.h;
+    const int leftA = a.x, rightA = a.x + a.w, topA = a.y, bottomA = a.y + a.h;
+    const int leftB = b.x, rightB = b.x + b.w, topB = b.y, bottomB = b.y + b.h;
 
-    // Calcula las caras del rectangulo b
-    const int leftB = b.x;
-    const int rightB = b.x + b.w;
-    const int topB = b.y;
-    const int bottomB = b.y + b.h;
-
-    // Si cualquiera de las caras de a está fuera de b
     if (bottomA <= topB)
-    {
         return false;
-    }
-
     if (topA >= bottomB)
-    {
         return false;
-    }
-
     if (rightA <= leftB)
-    {
         return false;
-    }
-
     if (leftA >= rightB)
-    {
         return false;
-    }
 
-    // Si ninguna de las caras está fuera de b
     return true;
 }
 
 // Detector de colisiones entre un punto y un rectangulo
-bool checkCollision(SDL_Point &p, SDL_Rect &r)
+bool checkCollision(const SDL_Point &p, const SDL_Rect &r)
 {
-    // Comprueba si el punto está a la izquierda del rectangulo
-    if (p.x < r.x)
-    {
+    if (p.x < r.x || p.x > r.x + r.w)
         return false;
-    }
-
-    // Comprueba si el punto está a la derecha del rectangulo
-    if (p.x > r.x + r.w)
-    {
+    if (p.y < r.y || p.y > r.y + r.h)
         return false;
-    }
-
-    // Comprueba si el punto está por encima del rectangulo
-    if (p.y < r.y)
-    {
-        return false;
-    }
-
-    // Comprueba si el punto está por debajo del rectangulo
-    if (p.y > r.y + r.h)
-    {
-        return false;
-    }
-
-    // Si no está fuera, es que está dentro
     return true;
 }
 
 // Convierte una cadena en un valor booleano
-bool stringToBool(std::string str)
+bool stringToBool(const std::string &str)
 {
-    return str == "true" ? true : false;
+    return str == "true";
 }
 
 // Convierte un valor booleano en una cadena
 std::string boolToString(bool value)
 {
-    return value == true ? "true" : "false";
+    return value ? "true" : "false";
 }
 
 // Convierte un valor booleano en una cadena "on" o "off"
 std::string boolToOnOff(bool value)
 {
-    return value == true ? "on" : "off";
+    return value ? "on" : "off";
 }
 
 // Convierte una cadena a minusculas
-std::string toLower(std::string str)
+std::string toLower(const std::string &str)
 {
-    const char *original = str.c_str();
-    char *lower = (char *)malloc(str.size() + 1);
-    for (int i = 0; i < (int)str.size(); ++i)
-    {
-        char c = original[i];
-        lower[i] = (c >= 65 && c <= 90) ? c + 32 : c;
-    }
-    lower[str.size()] = 0;
-    std::string nova(lower);
-    free(lower);
-    return nova;
+    std::string result = str;
+    std::transform(result.begin(), result.end(), result.begin(),
+                   [](unsigned char c)
+                   { return std::tolower(c); });
+    return result;
 }
 
 // Obtiene el fichero de sonido a partir de un nombre
-JA_Sound_t *getSound(std::vector<SoundFile> sounds, std::string name)
+JA_Sound_t *getSound(const std::vector<SoundFile> &sounds, const std::string &name)
 {
-    for (auto s : sounds)
+    for (const auto &s : sounds)
     {
         if (s.name == name)
         {
             return s.file;
         }
     }
-
     return nullptr;
 }
 
 // Obtiene el fichero de música a partir de un nombre
-JA_Music_t *getMusic(std::vector<MusicFile> music, std::string name)
+JA_Music_t *getMusic(const std::vector<MusicFile> &music, const std::string &name)
 {
-    for (auto m : music)
+    for (const auto &m : music)
     {
         if (m.name == name)
         {
             return m.file;
         }
     }
-
     return nullptr;
 }
 
 // Ordena las entradas de la tabla de records
-HiScoreEntry sortHiScoreTable(HiScoreEntry entry1, HiScoreEntry entry2)
+HiScoreEntry sortHiScoreTable(const HiScoreEntry &entry1, const HiScoreEntry &entry2)
 {
-    if (entry1.score > entry2.score)
-    {
-        return entry1;
-    }
-
-    return entry2;
+    return (entry1.score > entry2.score) ? entry1 : entry2;
 }
 
 // Dibuja un circulo
@@ -275,41 +177,31 @@ void DrawCircle(SDL_Renderer *renderer, int32_t centerX, int32_t centerY, int32_
 }
 
 // Aclara el color
-Color lightenColor(Color color, int amount)
+Color lightenColor(const Color &color, int amount)
 {
     Color newColor;
-    newColor.r = std::min(255, (int)color.r + amount);
-    newColor.g = std::min(255, (int)color.g + amount);
-    newColor.b = std::min(255, (int)color.b + amount);
+    newColor.r = std::min(255, color.r + amount);
+    newColor.g = std::min(255, color.g + amount);
+    newColor.b = std::min(255, color.b + amount);
     return newColor;
 }
 
 // Oscurece el color
-Color DarkenColor(Color color, int amount)
+Color DarkenColor(const Color &color, int amount)
 {
     Color newColor;
-    newColor.r = std::max(0, (int)color.r - amount);
-    newColor.g = std::max(0, (int)color.g - amount);
-    newColor.b = std::max(0, (int)color.b - amount);
+    newColor.r = std::min(255, color.r - +amount);
+    newColor.g = std::min(255, color.g - +amount);
+    newColor.b = std::min(255, color.b - +amount);
     return newColor;
 }
 
 // Quita los espacioes en un string
 std::string trim(const std::string &str)
 {
-    auto start = str.begin();
-    while (start != str.end() && std::isspace(*start))
-    {
-        start++;
-    }
-
-    auto end = str.end();
-    do
-    {
-        end--;
-    } while (std::distance(start, end) > 0 && std::isspace(*end));
-
-    return std::string(start, end + 1);
+    auto start = std::find_if_not(str.begin(), str.end(), ::isspace);
+    auto end = std::find_if_not(str.rbegin(), str.rend(), ::isspace).base();
+    return (start < end ? std::string(start, end) : std::string());
 }
 
 // Función de suavizado
diff --git a/source/utils.h b/source/utils.h
index a1fac60..c40143d 100644
--- a/source/utils.h
+++ b/source/utils.h
@@ -235,19 +235,19 @@ struct MusicFile
 double distanceSquared(int x1, int y1, int x2, int y2);
 
 // Detector de colisiones entre dos circulos
-bool checkCollision(Circle &a, Circle &b);
+bool checkCollision(const Circle &a, const Circle &b);
 
 // Detector de colisiones entre un circulo y un rectangulo
-bool checkCollision(Circle &a, SDL_Rect &b);
+bool checkCollision(const Circle &a, const SDL_Rect &b);
 
 // Detector de colisiones entre un dos rectangulos
-bool checkCollision(SDL_Rect &a, SDL_Rect &b);
+bool checkCollision(const SDL_Rect &a, const SDL_Rect &b);
 
 // Detector de colisiones entre un punto y un rectangulo
-bool checkCollision(SDL_Point &p, SDL_Rect &r);
+bool checkCollision(const SDL_Point &p, const SDL_Rect &r);
 
 // Convierte una cadena en un valor booleano
-bool stringToBool(std::string str);
+bool stringToBool(const std::string &str);
 
 // Convierte un valor booleano en una cadena
 std::string boolToString(bool value);
@@ -256,25 +256,25 @@ std::string boolToString(bool value);
 std::string boolToOnOff(bool value);
 
 // Convierte una cadena a minusculas
-std::string toLower(std::string str);
+std::string toLower(const std::string &str);
 
 // Obtiene el fichero de sonido a partir de un nombre
-JA_Sound_t *getSound(std::vector<SoundFile> sounds, std::string name);
+JA_Sound_t *getSound(const std::vector<SoundFile> &sounds, const std::string &name);
 
 // Obtiene el fichero de música a partir de un nombre
-JA_Music_t *getMusic(std::vector<MusicFile> music, std::string name);
+JA_Music_t *getMusic(const std::vector<MusicFile> &music, const std::string &name);
 
 // Ordena las entradas de la tabla de records
-HiScoreEntry sortHiScoreTable(HiScoreEntry entry1, HiScoreEntry entry2);
+HiScoreEntry sortHiScoreTable(const HiScoreEntry &entry1, const HiScoreEntry &entry2);
 
 // Dibuja un circulo
 void DrawCircle(SDL_Renderer *renderer, int32_t centerX, int32_t centerY, int32_t radius);
 
 // Aclara el color
-Color lightenColor(Color color, int amount);
+Color lightenColor(const Color &color, int amount);
 
 // Oscurece el color
-Color DarkenColor(Color color, int amount);
+Color DarkenColor(const Color &color, int amount);
 
 // Quita los espacioes en un string
 std::string trim(const std::string &str);
diff --git a/source/writer.h b/source/writer.h
index 9e1419e..ba03ce4 100644
--- a/source/writer.h
+++ b/source/writer.h
@@ -4,7 +4,7 @@
 #include <memory>
 #include "text.h"
 
-// Clase Writer. Pinta texto en pantalla letra a letra a partir de una cadena y un bitmap
+// Clase Writer. Pinta texto en pantalla letra a letra a partir de una cadena y un objeto Text
 class Writer
 {
 private: