/**** 
* Classes
****/ 
var Bubble = Container.expand(function () {
	var self = Container.call(this);
	var bubbleGraphics = self.attachAsset('bubble', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	bubbleGraphics.width *= 0.7;
	bubbleGraphics.height *= 0.7;
	self.speed = 45;
	self._move_migrated = function () {
		self.x += Math.cos(self.rotation) * self.speed;
		self.y += Math.sin(self.rotation) * self.speed;
	};
});
var BubbleUI = Container.expand(function () {
	var self = Container.call(this);
	self.bubbles = [];
	var bubble = self.attachAsset('bubble', {
		anchorY: 0.5
	});
	var totalWidth = 4 * (bubble.width + 10) - 10;
	self.x = (2048 - totalWidth) / 2;
	for (var i = 0; i < 4; i++) {
		var bubble = self.attachAsset('bubble', {
			anchorY: 0.5
		});
		bubble.x = i * (bubble.width + 10);
		bubble.y = 0;
		self.bubbles.push(bubble);
		self.addChild(bubble);
	}
	self.updateBubbles = function (lives) {
		for (var i = 0; i < self.bubbles.length; i++) {
			if (i < lives) {
				self.bubbles[i].tint = 0xFFFFFF;
				if (!self.bubbles[i].restored) {
					var lifeRestoration = new LifeRestorationAsset();
					self.addChild(lifeRestoration);
					lifeRestoration.show(self.bubbles[i].x + self.bubbles[i].width / 2, self.bubbles[i].y - lifeRestoration.height / 2 + 65);
					self.bubbles[i].restored = true;
				}
			} else {
				self.bubbles[i].tint = 0x000000;
				self.bubbles[i].restored = false;
			}
		}
	};
	self.y = 2732 - self.bubbles[0].height - 5;
});
var DuckHoldingSign = Container.expand(function () {
	var self = Container.call(this);
	var duckGraphics = self.attachAsset('duck_holding_a_sign', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.visible = false;
	self.show = function (x, y) {
		self.x = x;
		self.y = y;
		self.visible = true;
		LK.setTimeout(function () {
			self.visible = false;
		}, 1000);
	};
});
var LifeRestorationAsset = Container.expand(function () {
	var self = Container.call(this);
	var lifeRestorationGraphics = self.attachAsset('lifeRestoration', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.show = function (x, y) {
		self.x = x;
		self.y = y;
		self.visible = true;
		LK.setTimeout(function () {
			self.destroy();
		}, 500);
	};
});
var Shooter = Container.expand(function () {
	var self = Container.call(this);
	self.rotationAngle = 0;
	var shooterGraphics = self.attachAsset('cannon', {
		anchorX: 0.5,
		anchorY: 1
	});
	var cannonSize = Math.min(shooterGraphics.width, shooterGraphics.height) * 0.375;
	shooterGraphics.width = cannonSize;
	shooterGraphics.height = cannonSize;
});
var Skater = Container.expand(function () {
	var self = Container.call(this);
	var skaterGraphics = self.attachAsset('skater', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.direction = Math.random() * 2 * Math.PI;
	self.speed = 3;
	self.rotationSpeed = 0.05;
	self.isRotating = false;
	self.rotateTimer = 0;
	self.rotateDuration = 60;
	self._move_migrated = function () {
		var newX = self.x + Math.cos(self.direction) * self.speed;
		var newY = self.y + Math.sin(self.direction) * self.speed;
		if (newX > 1798 || newX < 300) {
			self.direction = Math.PI - self.direction;
		}
		if (newY > 2482 || newY < 250) {
			self.direction = -self.direction;
		}
		self.x = newX;
		self.y = newY;
	};
	self._update_migrated = function () {
		if (self.isRotating) {
			self.rotation += self.rotationSpeed * 0.5;
			self.rotateTimer++;
			if (self.rotateTimer >= self.rotateDuration) {
				self.isRotating = false;
				self.rotateTimer = 0;
				self.direction = Math.random() * 2 * Math.PI;
			}
		} else if (Math.random() < 0.01) {
			self.isRotating = true;
		}
		self._move_migrated();
		for (var i = 0; i < skaters.length; i++) {
			if (self !== skaters[i] && self.intersects(skaters[i])) {
				var angle = Math.atan2(skaters[i].y - self.y, skaters[i].x - self.x);
				self.direction = angle + Math.PI;
				skaters[i].direction = angle;
				// Play Bounce sound when skaters touch each other
				LK.getSound('Bounce').play();
			}
		}
		var circleCenter = {
			x: 2048 / 2,
			y: 2732 / 2
		};
		var distanceToCenter = Math.sqrt(Math.pow(self.x - circleCenter.x, 2) + Math.pow(self.y - circleCenter.y, 2));
		if (distanceToCenter < 400) {
			var angle = Math.atan2(circleCenter.y - self.y, circleCenter.x - self.x);
			self.direction = angle + Math.PI;
		}
	};
});
var Snowboarder = Container.expand(function () {
	var self = Container.call(this);
	var snowboarderGraphics = self.attachAsset('snowboarder', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.direction = Math.random() * 2 * Math.PI;
	self.speed = 3;
	self.rotationSpeed = 0.05;
	self.isRotating = false;
	self.rotateTimer = 0;
	self.rotateDuration = 60;
	self._move_migrated = function () {
		var newX = self.x + Math.cos(self.direction) * self.speed;
		var newY = self.y + Math.sin(self.direction) * self.speed;
		if (newX > 1798 || newX < 300) {
			self.direction = Math.PI - self.direction;
		}
		if (newY > 2482 || newY < 250) {
			self.direction = -self.direction;
		}
		self.x = newX;
		self.y = newY;
	};
	self._update_migrated = function () {
		if (self.isRotating) {
			self.rotation += self.rotationSpeed * 0.5;
			self.rotateTimer++;
			if (self.rotateTimer >= self.rotateDuration) {
				self.isRotating = false;
				self.rotateTimer = 0;
				self.direction = Math.random() * 2 * Math.PI;
			}
		} else if (Math.random() < 0.01) {
			self.isRotating = true;
		}
		self._move_migrated();
		for (var i = 0; i < skaters.length; i++) {
			if (self !== skaters[i] && self.intersects(skaters[i])) {
				var angle = Math.atan2(skaters[i].y - self.y, skaters[i].x - self.x);
				self.direction = angle + Math.PI;
				skaters[i].direction = angle;
				// Play Bounce sound when snowboarders and skaters touch each other
				LK.getSound('Bounce').play();
			}
		}
		var circleCenter = {
			x: 2048 / 2,
			y: 2732 / 2
		};
		var distanceToCenter = Math.sqrt(Math.pow(self.x - circleCenter.x, 2) + Math.pow(self.y - circleCenter.y, 2));
		if (distanceToCenter < 400) {
			var angle = Math.atan2(circleCenter.y - self.y, circleCenter.x - self.x);
			self.direction = angle + Math.PI;
		}
	};
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x000000
});

/**** 
* Game Code
****/ 
var skaters = [];
LK.playMusic('backgroundMusic', {
	loop: true
});
game.on('move', function (x, y, obj) {
	game.levelUp = function () {
		game.levelTransitionInProgress = true;
		game.level++;
		game.setLives(4);
		skaters.forEach(function (entity) {
			if (entity instanceof Snowboarder) {
				entity.destroy();
			}
		});
		skaters = skaters.filter(function (entity) {
			return !(entity instanceof Snowboarder);
		});
		game.spawnSkaters(game.level);
		game.levelTransitionInProgress = false;
		// Play NewRound sound when a new round starts
		LK.getSound('NewRound').play();
		game.levelTransitionInitiated = false;
	};
	var event = obj;
	var pos = game.toLocal(event.global);
	var angle = Math.atan2(pos.y - shooter.y, pos.x - shooter.x) + Math.PI / 2;
	shooter.rotation = angle;
});
game.on('up', function (x, y, obj) {
	if (game.lives > 0 && !game.levelTransitionInitiated && !game.levelTransitionInProgress) {
		var event = obj;
		var pos = game.toLocal(event.global);
		var newBubble = game.addChild(new Bubble());
		newBubble.rotation = Math.atan2(pos.y - shooter.y, pos.x - shooter.x);
		newBubble.x = shooter.x;
		newBubble.y = shooter.y;
		bubbles.push(newBubble);
		if (game.lives > 0) {
			game.lives--;
			// Play Snowball sound
			LK.getSound('Snowball').play();
		}
		bubbleUI.updateBubbles(game.lives);
	}
});
game.level = 1;
game.levelTransitionInitiated = false;
game.levelTransitionInProgress = false;
var bubbleUI = game.addChild(new BubbleUI());
game.setLives = function (lives) {
	game.lives = lives;
	bubbleUI.updateBubbles(game.lives);
};
game.setLives(4);
game.score = 0;
var scoreText = new Text2(game.score.toString(), {
	size: 150,
	fill: "#ffffff",
	stroke: "#075079",
	strokeThickness: 11.25,
	font: "'Luckiest Guy', 'Arial Black', sans-serif"
});
scoreText.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreText);
game.spawnSkaters = function (level) {
	for (var i = 0; i < level + 4; i++) {
		var skater = game.addChild(new Skater());
		do {
			skater.x = 300 + Math.random() * (2048 - 600);
			skater.y = 250 + Math.random() * (2732 - 500);
		} while (Math.sqrt(Math.pow(skater.x - 2048 / 2, 2) + Math.pow(skater.y - 2732 / 2, 2)) < 400);
		skaters.push(skater);
	}
	var numberOfSnowboarders = Math.max(0, Math.ceil((game.level - 1) / 2));
	for (var sb = 0; sb < numberOfSnowboarders; sb++) {
		var snowboarder = game.addChild(new Snowboarder());
		do {
			snowboarder.x = 300 + Math.random() * (2048 - 600);
			snowboarder.y = 250 + Math.random() * (2732 - 500);
		} while (Math.sqrt(Math.pow(snowboarder.x - 2048 / 2, 2) + Math.pow(snowboarder.y - 2732 / 2, 2)) < 400);
		skaters.push(snowboarder);
	}
};
isGameOver = false;
game.levelCompleted = true;
if (!game.levelTransitionInitiated) {
	game.spawnSkaters(game.level);
}
var backgroundLayer2 = game.attachAsset('backgroundLayer2', {
	anchorX: 0.5,
	anchorY: 0.5
});
backgroundLayer2.width = 2048;
backgroundLayer2.height = 2732;
backgroundLayer2.x = 2048 / 2;
backgroundLayer2.y = 2732 / 2;
game.addChildAt(backgroundLayer2, 0);
var background = game.attachAsset('background', {
	anchorX: 0.5,
	anchorY: 0.5
});
background.width = 2048;
background.height = 2732;
background.x = 2048 / 2;
background.y = 2732 / 2;
game.addChildAt(background, 1);
var bubbles = [];
var bubbleHitEdge = false;
var shooter = game.addChild(new Shooter());
var duckHoldingSign = game.addChild(new DuckHoldingSign());
var currentCombo = 0;
var lastBubbleHit = false;
shooter.x = 2048 / 2;
shooter.y = 2732 / 2;
var circle = game.attachAsset('circle', {
	anchorX: 0.5,
	anchorY: 0.5
});
circle.width = 600;
circle.height = 600;
circle.alpha = 1;
circle.x = 2048 / 2;
circle.y = 2732 / 2;
game.addChildAt(circle, 2);
var isGameOver = false;
var tickOffset = 0;
LK.on('tick', function () {
	var levelCompleted = false;
	var gameOver = false;
	if (isGameOver) {
		LK.effects.flashScreen(0xff0000, 1000);
		LK.showGameOver();
	}
	for (var i = 0; i < skaters.length; i++) {
		skaters[i]._update_migrated();
	}
	for (var a = bubbles.length - 1; a >= 0; a--) {
		bubbles[a]._move_migrated();
		for (var s = skaters.length - 1; s >= 0; s--) {
			if (bubbles[a].intersects(skaters[s])) {
				if (skaters[s] instanceof Snowboarder) {
					isGameOver = true;
				} else if (skaters[s]) {
					var explosion = game.attachAsset('explosion', {
						anchorX: 0.5,
						anchorY: 0.5
					});
					explosion.x = skaters[s].x;
					explosion.y = skaters[s].y;
					game.addChild(explosion);
					LK.setTimeout(function () {
						explosion.destroy();
					}, 100);
					// Play Hit sound when an enemy dies
					LK.getSound('Hit').play();
					skaters[s].destroy();
					skaters.splice(s, 1);
					if (!bubbles[a].skatersHit) {
						bubbles[a].skatersHit = [];
					}
					bubbles[a].skatersHit.push(skaters[s]);
					var skaterScore = bubbles[a].skatersHit.length;
					LK.setScore(LK.getScore() + skaterScore);
					if (skaterScore >= 2) {
						if (game.lives < 4) {
							game.lives++;
							// Play Regen sound when a life is refilled
							LK.getSound('Regen').play();
							bubbleUI.updateBubbles(game.lives);
						}
						currentCombo++;
						duckHoldingSign.show(skaters[s].x, skaters[s].y);
					} else {
						currentCombo = 0;
					}
					scoreText.setText(LK.getScore().toString());
				}
				var skaterCount = skaters.filter(function (entity) {
					return !(entity instanceof Snowboarder);
				}).length;
				break;
			}
		}
		if (bubbles[a].x > 2048 || bubbles[a].x < 0 || bubbles[a].y > 2732 || bubbles[a].y < 0 || !bubbles[a].parent) {
			bubbleHitEdge = true;
			if (!bubbles[a].skatersHit || bubbles[a].skatersHit.length < 2) {
				currentCombo = 0;
			}
			bubbles[a].destroy();
			bubbles.splice(a, 1);
			var skaterCount = skaters.filter(function (entity) {
				return !(entity instanceof Snowboarder);
			}).length;
			if (skaterCount === 0 && !game.levelTransitionInitiated && !game.levelTransitionInProgress) {
				game.levelCompleted = true;
				game.levelTransitionInitiated = true;
				if (!game.levelTransitionInProgress) {
					LK.setScore(LK.getScore() + game.lives * 5);
					scoreText.setText(LK.getScore().toString());
					game.levelUp();
				}
			} else if (bubbles.length === 0 && game.lives === 0) {
				isGameOver = true;
			}
		}
	}
	var skaterCount = skaters.filter(function (entity) {
		return !(entity instanceof Snowboarder);
	}).length;
	if (skaterCount === 0 && bubbles.length === 0 && !game.levelTransitionInitiated && !game.levelTransitionInProgress) {
		game.levelCompleted = true;
		game.levelTransitionInitiated = true;
		LK.setTimeout(function () {
			if (!game.levelTransitionInProgress) {
				LK.setScore(LK.getScore() + game.lives * 5);
				scoreText.setText(LK.getScore().toString());
				game.levelUp();
			}
		}, 500);
	}
	if (!levelCompleted && game.lives === 0 && bubbles.length === 0 && !isGameOver) {
		gameOver = true;
	}
	if (gameOver) {
		isGameOver = true;
		LK.effects.flashScreen(0xff0000, 1000);
		LK.showGameOver();
	}
});

===================================================================
--- original.js
+++ change.js
@@ -49,8 +49,24 @@
 		}
 	};
 	self.y = 2732 - self.bubbles[0].height - 5;
 });
+var DuckHoldingSign = Container.expand(function () {
+	var self = Container.call(this);
+	var duckGraphics = self.attachAsset('duck_holding_a_sign', {
+		anchorX: 0.5,
+		anchorY: 0.5
+	});
+	self.visible = false;
+	self.show = function (x, y) {
+		self.x = x;
+		self.y = y;
+		self.visible = true;
+		LK.setTimeout(function () {
+			self.visible = false;
+		}, 1000);
+	};
+});
 var LifeRestorationAsset = Container.expand(function () {
 	var self = Container.call(this);
 	var lifeRestorationGraphics = self.attachAsset('lifeRestoration', {
 		anchorX: 0.5,
@@ -309,8 +325,11 @@
 game.addChildAt(background, 1);
 var bubbles = [];
 var bubbleHitEdge = false;
 var shooter = game.addChild(new Shooter());
+var duckHoldingSign = game.addChild(new DuckHoldingSign());
+var currentCombo = 0;
+var lastBubbleHit = false;
 shooter.x = 2048 / 2;
 shooter.y = 2732 / 2;
 var circle = game.attachAsset('circle', {
 	anchorX: 0.5,
@@ -367,8 +386,12 @@
 							// Play Regen sound when a life is refilled
 							LK.getSound('Regen').play();
 							bubbleUI.updateBubbles(game.lives);
 						}
+						currentCombo++;
+						duckHoldingSign.show(skaters[s].x, skaters[s].y);
+					} else {
+						currentCombo = 0;
 					}
 					scoreText.setText(LK.getScore().toString());
 				}
 				var skaterCount = skaters.filter(function (entity) {
@@ -378,8 +401,11 @@
 			}
 		}
 		if (bubbles[a].x > 2048 || bubbles[a].x < 0 || bubbles[a].y > 2732 || bubbles[a].y < 0 || !bubbles[a].parent) {
 			bubbleHitEdge = true;
+			if (!bubbles[a].skatersHit || bubbles[a].skatersHit.length < 2) {
+				currentCombo = 0;
+			}
 			bubbles[a].destroy();
 			bubbles.splice(a, 1);
 			var skaterCount = skaters.filter(function (entity) {
 				return !(entity instanceof Snowboarder);