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

/**** 
* Classes
****/ 
var Bird = Container.expand(function () {
	var self = Container.call(this);
	var birdGraphics = self.attachAsset('bird', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.velocityY = 0;
	self.gravity = 0.6;
	self.flapPower = -12;
	self.isAlive = true;
	self.flap = function () {
		self.velocityY = self.flapPower;
		LK.getSound('flap').play();
	};
	self.update = function () {
		if (!self.isAlive) return;
		self.velocityY += self.gravity;
		self.lastY = self.y;
		self.y += self.velocityY;
		if (self.lastY - 25 >= 0 && self.y - 25 < 0) {
			self.isAlive = false;
			LK.showGameOver();
		}
		if (self.y - 25 < 0) {
			self.y = 25;
			self.velocityY = 0;
		}
	};
	return self;
});
var Coin = Container.expand(function () {
	var self = Container.call(this);
	var coinGraphics = self.attachAsset('coin', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = -6;
	self.isCollected = false;
	self.update = function () {
		self.x += self.speed;
	};
	return self;
});
var Ground = Container.expand(function () {
	var self = Container.call(this);
	var groundGraphics = self.attachAsset('ground', {
		anchorX: 0,
		anchorY: 0
	});
	self.x = 0;
	self.y = 2582;
	return self;
});
var Pipe = Container.expand(function () {
	var self = Container.call(this);
	self.speed = -6;
	self.gapSize = 250;
	self.hasBeenScored = false;
	var topPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 1
	});
	var bottomPipe = self.attachAsset('pipe', {
		anchorX: 0.5,
		anchorY: 0
	});
	self.setup = function (gapY) {
		self.gapY = gapY;
		topPipe.y = gapY - self.gapSize / 2;
		bottomPipe.y = gapY + self.gapSize / 2;
		topPipe.x = 50;
		bottomPipe.x = 50;
	};
	self.update = function () {
		self.x += self.speed;
	};
	return self;
});

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

/**** 
* Game Code
****/ 
var bird = game.addChild(new Bird());
bird.x = 300;
bird.y = 1366;
bird.lastY = bird.y;
bird.lastWasCollidingWithPipe = false;
var ground = game.addChild(new Ground());
var pipes = [];
var coins = [];
var pipeSpawnTimer = 0;
var pipeSpawnInterval = 200;
var nextGapPosition = 0;
var currentLevel = 1;
var pipsPassedInLevel = 0;
var pipsRequiredToLevelUp = 5;
var coinsCollected = 0;
var scoreTxt = new Text2('Score: 0', {
	size: 120,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
scoreTxt.y = 20;
LK.gui.top.addChild(scoreTxt);
var gameScore = 0;
var levelTxt = new Text2('Level 1', {
	size: 100,
	fill: 0xFFFFFF
});
levelTxt.anchor.set(0.5, 0);
levelTxt.y = 150;
LK.gui.top.addChild(levelTxt);
function spawnPipe() {
	var minGapY = 400;
	var maxGapY = 1800;
	var randomGapY = minGapY + Math.random() * (maxGapY - minGapY);
	var newPipe = game.addChild(new Pipe());
	newPipe.x = 2048 + 100;
	var basePipeGapSize = newPipe.gapSize;
	newPipe.gapSize = Math.max(150, basePipeGapSize - (currentLevel - 1) * 15);
	newPipe.setup(randomGapY);
	newPipe.lastX = newPipe.x;
	newPipe.hasBeenScored = false;
	pipes.push(newPipe);
	var coinOffset = (Math.random() - 0.5) * 150;
	var newCoin = game.addChild(new Coin());
	newCoin.x = newPipe.x;
	newCoin.y = randomGapY + coinOffset;
	newCoin.lastX = newCoin.x;
	newCoin.isCollected = false;
	coins.push(newCoin);
}
game.down = function (x, y, obj) {
	if (bird.isAlive) {
		bird.flap();
	}
};
game.update = function () {
	bird.update();
	pipeSpawnTimer++;
	var currentSpawnInterval = Math.max(120, pipeSpawnInterval - (currentLevel - 1) * 15);
	if (pipeSpawnTimer >= currentSpawnInterval) {
		spawnPipe();
		pipeSpawnTimer = 0;
	}
	for (var i = coins.length - 1; i >= 0; i--) {
		var coin = coins[i];
		coin.update();
		if (!coin.lastX) coin.lastX = coin.x;
		if (coin.x < -100) {
			coin.destroy();
			coins.splice(i, 1);
		}
		if (bird.isAlive && !coin.isCollected) {
			var coinCollisionDistance = Math.sqrt((bird.x - coin.x) * (bird.x - coin.x) + (bird.y - coin.y) * (bird.y - coin.y));
			if (coinCollisionDistance < 50) {
				coin.isCollected = true;
				coinsCollected++;
				LK.getSound('coin').play();
				coin.destroy();
				coins.splice(i, 1);
			}
		}
	}
	for (var i = pipes.length - 1; i >= 0; i--) {
		var pipe = pipes[i];
		pipe.update();
		if (!pipe.lastX) pipe.lastX = pipe.x;
		if (pipe.lastX > 300 && pipe.x <= 300 && !pipe.hasBeenScored) {
			pipe.hasBeenScored = true;
			gameScore++;
			LK.setScore(gameScore);
			pipsPassedInLevel++;
			scoreTxt.setText('Score: ' + gameScore);
			LK.getSound('score').play();
			if (pipsPassedInLevel >= pipsRequiredToLevelUp) {
				currentLevel++;
				pipsPassedInLevel = 0;
				levelTxt.setText('Level ' + currentLevel);
			}
		}
		pipe.lastX = pipe.x;
		if (pipe.x < -150) {
			pipe.destroy();
			pipes.splice(i, 1);
		}
		if (bird.isAlive && bird.lastWasCollidingWithPipe === undefined) {
			bird.lastWasCollidingWithPipe = false;
		}
		if (bird.isAlive) {
			var birdLeft = bird.x - 25;
			var birdRight = bird.x + 25;
			var birdTop = bird.y - 25;
			var birdBottom = bird.y + 25;
			var pipeLeft = pipe.x - 50;
			var pipeRight = pipe.x + 50;
			var isCollidingNow = false;
			if (birdRight > pipeLeft && birdLeft < pipeRight) {
				if (birdTop < pipe.gapY - pipe.gapSize / 2 || birdBottom > pipe.gapY + pipe.gapSize / 2) {
					isCollidingNow = true;
				}
			}
			if (!bird.lastWasCollidingWithPipe && isCollidingNow) {
				bird.isAlive = false;
				LK.showGameOver();
			}
			bird.lastWasCollidingWithPipe = isCollidingNow;
		}
	}
};
LK.playMusic('bgmusic', {
	loop: true
});

===================================================================
--- original.js
+++ change.js
@@ -35,8 +35,21 @@
 		}
 	};
 	return self;
 });
+var Coin = Container.expand(function () {
+	var self = Container.call(this);
+	var coinGraphics = self.attachAsset('coin', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.speed = -6;
+	self.isCollected = false;
+	self.update = function () {
+		self.x += self.speed;
+	};
+	return self;
+});
 var Ground = Container.expand(function () {
 	var self = Container.call(this);
 	var groundGraphics = self.attachAsset('ground', {
 		anchorX: 0,
@@ -88,14 +101,16 @@
 bird.lastY = bird.y;
 bird.lastWasCollidingWithPipe = false;
 var ground = game.addChild(new Ground());
 var pipes = [];
+var coins = [];
 var pipeSpawnTimer = 0;
 var pipeSpawnInterval = 200;
 var nextGapPosition = 0;
 var currentLevel = 1;
 var pipsPassedInLevel = 0;
 var pipsRequiredToLevelUp = 5;
+var coinsCollected = 0;
 var scoreTxt = new Text2('Score: 0', {
 	size: 120,
 	fill: 0xFFFFFF
 });
@@ -121,8 +136,15 @@
 	newPipe.setup(randomGapY);
 	newPipe.lastX = newPipe.x;
 	newPipe.hasBeenScored = false;
 	pipes.push(newPipe);
+	var coinOffset = (Math.random() - 0.5) * 150;
+	var newCoin = game.addChild(new Coin());
+	newCoin.x = newPipe.x;
+	newCoin.y = randomGapY + coinOffset;
+	newCoin.lastX = newCoin.x;
+	newCoin.isCollected = false;
+	coins.push(newCoin);
 }
 game.down = function (x, y, obj) {
 	if (bird.isAlive) {
 		bird.flap();
@@ -135,8 +157,27 @@
 	if (pipeSpawnTimer >= currentSpawnInterval) {
 		spawnPipe();
 		pipeSpawnTimer = 0;
 	}
+	for (var i = coins.length - 1; i >= 0; i--) {
+		var coin = coins[i];
+		coin.update();
+		if (!coin.lastX) coin.lastX = coin.x;
+		if (coin.x < -100) {
+			coin.destroy();
+			coins.splice(i, 1);
+		}
+		if (bird.isAlive && !coin.isCollected) {
+			var coinCollisionDistance = Math.sqrt((bird.x - coin.x) * (bird.x - coin.x) + (bird.y - coin.y) * (bird.y - coin.y));
+			if (coinCollisionDistance < 50) {
+				coin.isCollected = true;
+				coinsCollected++;
+				LK.getSound('coin').play();
+				coin.destroy();
+				coins.splice(i, 1);
+			}
+		}
+	}
 	for (var i = pipes.length - 1; i >= 0; i--) {
 		var pipe = pipes[i];
 		pipe.update();
 		if (!pipe.lastX) pipe.lastX = pipe.x;