/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
var Enemy = Container.expand(function () {
	var self = Container.call(this);
	var enemyGraphics = self.attachAsset('enemy', {
		anchorX: 0.5,
		anchorY: 1
	});
	self.speed = gameSpeed;
	self.update = function () {
		self.x -= self.speed;
		// Simple enemy animation
		enemyGraphics.scaleX = 1 + Math.sin(LK.ticks * 0.15) * 0.1;
		enemyGraphics.scaleY = 1 + Math.sin(LK.ticks * 0.15) * 0.1;
	};
	return self;
});
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundGraphics = self.attachAsset('ground', {
		anchorX: 0,
		anchorY: 0
	});
	self.speed = gameSpeed;
	self.update = function () {
		self.x -= self.speed;
	};
	return self;
});
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	var obstacleGraphics = self.attachAsset('obstacle', {
		anchorX: 0.5,
		anchorY: 1
	});
	self.speed = gameSpeed;
	self.update = function () {
		self.x -= self.speed;
	};
	return self;
});
var Ring = Container.expand(function () {
	var self = Container.call(this);
	var ringGraphics = self.attachAsset('ring', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = gameSpeed;
	self.collected = false;
	self.update = function () {
		self.x -= self.speed;
		// Floating animation
		ringGraphics.y = Math.sin(LK.ticks * 0.1) * 5;
		ringGraphics.rotation += 0.1;
	};
	return self;
});
var Sonic = Container.expand(function () {
	var self = Container.call(this);
	var sonicGraphics = self.attachAsset('sonic', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocityY = 0;
	self.isJumping = false;
	self.groundY = 0;
	self.jump = function () {
		if (!self.isJumping) {
			self.velocityY = -18;
			self.isJumping = true;
			LK.getSound('jump').play();
		}
	};
	self.update = function () {
		// Gravity
		self.velocityY += 0.8;
		self.y += self.velocityY;
		// Check if landed
		if (self.y >= self.groundY) {
			self.y = self.groundY;
			self.velocityY = 0;
			self.isJumping = false;
		}
		// Simple running animation
		sonicGraphics.rotation += 0.2;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x87CEEB
});

/**** 
* Game Code
****/ 
var gameSpeed = 6;
var groundLevel = 2400;
var spawnDistance = 0;
var distanceScore = 0;
var speedIncreaseTimer = 0;
var currentMusicTrack = 'bgmusic';
var musicSpeedThreshold = 12;
// Game objects arrays
var groundPieces = [];
var obstacles = [];
var rings = [];
var enemies = [];
// Create Sonic
var sonic = game.addChild(new Sonic());
sonic.x = 300;
sonic.y = groundLevel - 100;
sonic.groundY = groundLevel - 100;
// UI Elements
var ringScoreText = new Text2('Anillos: 0', {
	size: 60,
	fill: 0xFFFFFF
});
ringScoreText.anchor.set(0, 0);
LK.gui.topLeft.addChild(ringScoreText);
ringScoreText.x = 120;
ringScoreText.y = 20;
var distanceText = new Text2('Distancia: 0m', {
	size: 50,
	fill: 0xFFFFFF
});
distanceText.anchor.set(0.5, 0);
LK.gui.top.addChild(distanceText);
distanceText.y = 20;
// Initialize ground
for (var i = 0; i < 15; i++) {
	var ground = game.addChild(new Ground());
	ground.x = i * 200;
	ground.y = groundLevel;
	groundPieces.push(ground);
}
// Input handling
game.down = function (x, y, obj) {
	sonic.jump();
};
function spawnObstacle() {
	var obstacle = game.addChild(new Obstacle());
	obstacle.x = 2048 + 100;
	obstacle.y = groundLevel;
	obstacles.push(obstacle);
}
function spawnRing() {
	var ring = game.addChild(new Ring());
	ring.x = 2048 + 100;
	ring.y = groundLevel - 80 - Math.random() * 120;
	rings.push(ring);
}
function spawnEnemy() {
	var enemy = game.addChild(new Enemy());
	enemy.x = 2048 + 100;
	enemy.y = groundLevel;
	enemies.push(enemy);
}
function updateScore() {
	ringScoreText.setText('Anillos: ' + LK.getScore());
	distanceText.setText('Distancia: ' + Math.floor(distanceScore) + 'm');
}
game.update = function () {
	// Update distance score
	distanceScore += gameSpeed * 0.1;
	// Increase speed over time
	speedIncreaseTimer++;
	if (speedIncreaseTimer >= 300) {
		// Every 5 seconds
		gameSpeed += 0.5;
		speedIncreaseTimer = 0;
		// Switch to speed-up music when game gets faster
		if (gameSpeed >= musicSpeedThreshold && currentMusicTrack !== 'speedup_music') {
			currentMusicTrack = 'speedup_music';
			LK.playMusic('speedup_music', {
				fade: {
					start: 0.3,
					end: 0.9,
					duration: 1000
				}
			});
		}
	}
	// Update spawn distance
	spawnDistance += gameSpeed;
	// Spawn objects
	if (spawnDistance >= 300) {
		var rand = Math.random();
		if (rand < 0.3) {
			spawnObstacle();
		} else if (rand < 0.6) {
			spawnRing();
		} else if (rand < 0.8) {
			spawnEnemy();
		}
		spawnDistance = 0;
	}
	// Update ground pieces
	for (var i = groundPieces.length - 1; i >= 0; i--) {
		var ground = groundPieces[i];
		ground.speed = gameSpeed;
		if (ground.x <= -200) {
			ground.x = (groundPieces.length - 1) * 200;
		}
	}
	// Update and check obstacles
	for (var i = obstacles.length - 1; i >= 0; i--) {
		var obstacle = obstacles[i];
		obstacle.speed = gameSpeed;
		if (obstacle.x < -100) {
			obstacle.destroy();
			obstacles.splice(i, 1);
			continue;
		}
		// Collision with sonic
		if (sonic.intersects(obstacle)) {
			LK.getSound('hit').play();
			LK.effects.flashScreen(0xFF0000, 1000);
			LK.showGameOver();
			return;
		}
	}
	// Update and check rings
	for (var i = rings.length - 1; i >= 0; i--) {
		var ring = rings[i];
		ring.speed = gameSpeed;
		if (ring.x < -100) {
			ring.destroy();
			rings.splice(i, 1);
			continue;
		}
		// Collection check
		if (!ring.collected && sonic.intersects(ring)) {
			ring.collected = true;
			LK.setScore(LK.getScore() + 1);
			LK.getSound('ring').play();
			// Ring collection effect
			tween(ring, {
				alpha: 0,
				scaleX: 2,
				scaleY: 2
			}, {
				duration: 300,
				onFinish: function onFinish() {
					ring.destroy();
				}
			});
			rings.splice(i, 1);
		}
	}
	// Update and check enemies
	for (var i = enemies.length - 1; i >= 0; i--) {
		var enemy = enemies[i];
		enemy.speed = gameSpeed;
		if (enemy.x < -100) {
			enemy.destroy();
			enemies.splice(i, 1);
			continue;
		}
		// Collision with sonic
		if (sonic.intersects(enemy)) {
			LK.getSound('hit').play();
			LK.effects.flashScreen(0xFF0000, 1000);
			LK.showGameOver();
			return;
		}
	}
	// Update UI
	updateScore();
	// Win condition - collect 50 rings
	if (LK.getScore() >= 50) {
		LK.playMusic('victory_music', {
			loop: false,
			fade: {
				start: 0.2,
				end: 0.7,
				duration: 800
			}
		});
		LK.showYouWin();
		return;
	}
};
// Start background music with fade-in effect
LK.playMusic('bgmusic', {
	fade: {
		start: 0,
		end: 0.8,
		duration: 1500
	}
});

===================================================================
--- original.js
+++ change.js
@@ -107,8 +107,10 @@
 var groundLevel = 2400;
 var spawnDistance = 0;
 var distanceScore = 0;
 var speedIncreaseTimer = 0;
+var currentMusicTrack = 'bgmusic';
+var musicSpeedThreshold = 12;
 // Game objects arrays
 var groundPieces = [];
 var obstacles = [];
 var rings = [];
@@ -175,8 +177,19 @@
 	if (speedIncreaseTimer >= 300) {
 		// Every 5 seconds
 		gameSpeed += 0.5;
 		speedIncreaseTimer = 0;
+		// Switch to speed-up music when game gets faster
+		if (gameSpeed >= musicSpeedThreshold && currentMusicTrack !== 'speedup_music') {
+			currentMusicTrack = 'speedup_music';
+			LK.playMusic('speedup_music', {
+				fade: {
+					start: 0.3,
+					end: 0.9,
+					duration: 1000
+				}
+			});
+		}
 	}
 	// Update spawn distance
 	spawnDistance += gameSpeed;
 	// Spawn objects
@@ -264,10 +277,24 @@
 	// Update UI
 	updateScore();
 	// Win condition - collect 50 rings
 	if (LK.getScore() >= 50) {
+		LK.playMusic('victory_music', {
+			loop: false,
+			fade: {
+				start: 0.2,
+				end: 0.7,
+				duration: 800
+			}
+		});
 		LK.showYouWin();
 		return;
 	}
 };
-// Start background music
-LK.playMusic('bgmusic');
\ No newline at end of file
+// Start background music with fade-in effect
+LK.playMusic('bgmusic', {
+	fade: {
+		start: 0,
+		end: 0.8,
+		duration: 1500
+	}
+});
\ No newline at end of file