/**** 
* Classes
****/ 
// Create BackgroundContainer class
var BackgroundContainer = Container.expand(function () {
	var self = Container.call(this);
	return self;
});
// Create DigestionSystem class
var DigestionSystem = Container.expand(function () {
	var self = Container.call(this);
	self.units = [];
	self.maxUnits = 10;
	self.unitWidth = 100;
	self.unitHeight = 100;
	self.unitSpacing = 10;
	self.unitFullAlpha = 1;
	self.unitEmptyAlpha = 0.5;
	// Initialize with 10 empty units
	for (var i = 0; i < self.maxUnits; i++) {
		var unit = self.attachAsset('Unit', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: i * (self.unitWidth + self.unitSpacing),
			alpha: self.unitEmptyAlpha
		});
		self.units.push(unit);
	}
	return self;
});
// Create Food class
var Food = Container.expand(function () {
	var self = Container.call(this);
	// Attach Food asset to the food
	self.foodAsset = self.attachAsset('Food', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Set food speed
	self.speed = -10;
	// This is automatically called every game tick, if the food is attached!
	self.update = function () {
		self.x += self.speed;
	};
	return self;
});
// Create ForegroundContainer class
var ForegroundContainer = Container.expand(function () {
	var self = Container.call(this);
	return self;
});
// Create MidgroundContainer class
var MidgroundContainer = Container.expand(function () {
	var self = Container.call(this);
	return self;
});
// Create Player class
var Player = Container.expand(function () {
	var self = Container.call(this);
	// Attach Player_Up asset to the player
	self.playerUp = self.attachAsset('Player_Up', {
		anchorX: 0.5,
		anchorY: 1.0,
		scaleX: 1.5,
		scaleY: 1.5
	});
	// Attach Player_Down asset to the player
	self.playerDown = self.attachAsset('Player_Down', {
		anchorX: 0.5,
		anchorY: 1.0,
		x: -120,
		scaleX: 1.5,
		scaleY: 1.5
	});
	// Initially, Player_Down is not visible
	self.playerDown.visible = false;
	// Method to switch between Player_Up and Player_Down
	self.switchFrame = function () {
		self.playerUp.visible = !self.playerUp.visible;
		self.playerDown.visible = !self.playerDown.visible;
		if (self.playerDown.visible) {
			LK.getSound('Pooping').play();
		} else {
			LK.getSound('Pooping').stop();
		}
	};
	// Method to check if the player collides with a food object
	self.checkCollision = function (food) {
		// Only player_up can collect food
		if (self.playerUp.visible) {
			var playerBounds = self.playerUp.getBounds();
			var foodBounds = food.getBounds();
			var playerCenter = {
				x: playerBounds.x + playerBounds.width / 2,
				y: playerBounds.y + playerBounds.height / 2
			};
			var foodCenter = {
				x: foodBounds.x + foodBounds.width / 2,
				y: foodBounds.y + foodBounds.height / 2
			};
			// Check if the center of the food is within the bounds of the player
			if (playerBounds.contains(foodCenter.x, foodCenter.y)) {
				// Add a unit to the Digestion System
				var fullUnits = digestionSystem.units.filter(function (unit) {
					return unit.alpha === digestionSystem.unitFullAlpha;
				});
				if (fullUnits.length < digestionSystem.maxUnits && digestionSystem.units[fullUnits.length]) {
					digestionSystem.units[fullUnits.length].alpha = digestionSystem.unitFullAlpha;
				} else {
					// Game over if the Digestion System is full
					LK.showGameOver();
				}
				return true;
			}
			return false;
		}
		return false;
	};
	return self;
});

/**** 
* Initialize Game
****/ 
//<Assets used in the game will automatically appear here>
var game = new LK.Game({
	backgroundColor: 0x87CEEB // Init game with sky blue background
});

/**** 
* Game Code
****/ 
var backgroundContainer = game.addChild(new BackgroundContainer());
var midgroundContainer = game.addChild(new MidgroundContainer());
var foregroundContainer = game.addChild(new ForegroundContainer());
// Add the Digestion System to the game
var digestionSystem = game.addChild(new DigestionSystem());
digestionSystem.x = 2048 / 2 - digestionSystem.unitWidth * digestionSystem.maxUnits / 2;
digestionSystem.y = 100;
var score;
var scoreTxt = new Text2('0', {
	size: 150,
	fill: "#ffffff",
	stroke: "#000000",
	strokeThickness: 15
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
scoreTxt.y += 100;
// Add the Player in the center of the screen
var player = midgroundContainer.addChild(new Player());
player.x = 2048 / 2 - 500;
player.y = 2732 + 30;
// Switch the player's frame on tap
game.down = function (x, y, obj) {
	player.switchFrame();
};
// Spawn food from the right edge of the screen at y position of 500
game.update = function () {
	if (LK.ticks == 0) {
		score = 0;
		scoreTxt.setText(score);
		// Reset the Digestion System
		digestionSystem.units.forEach(function (unit) {
			unit.alpha = digestionSystem.unitEmptyAlpha;
		});
		// Ensure the state of the digestive system does not persist between game sessions
		digestionSystem.units = [];
	}
	if (LK.ticks % 60 == 0) {
		// every second
		var newFood = new Food();
		newFood.x = 2048; // right edge of the screen
		newFood.y = 1900;
		foregroundContainer.addChild(newFood);
	}
	// Check for collision between the player and the food
	// Remove a unit from the Digestion System when the player is in the Down state
	if (!player.playerUp.visible) {
		if (LK.ticks % 30 == 0) {
			var fullUnits = digestionSystem.units.filter(function (unit) {
				return unit.alpha === digestionSystem.unitFullAlpha;
			});
			if (fullUnits.length > 0) {
				fullUnits[fullUnits.length - 1].alpha = digestionSystem.unitEmptyAlpha;
			} else {
				LK.getSound('Pooping').stop();
			}
		}
	} else {
		LK.getSound('Pooping').stop();
	}
	for (var i = foregroundContainer.children.length - 1; i >= 0; i--) {
		var food = foregroundContainer.children[i];
		if (player.checkCollision(food)) {
			// Increment the score
			score++;
			scoreTxt.setText(score);
			// Play the Eat sound
			LK.getSound('Eat').play();
			// Remove the food from the game
			food.destroy();
		}
	}
};

===================================================================
--- original.js
+++ change.js
@@ -103,9 +103,9 @@
 				// Add a unit to the Digestion System
 				var fullUnits = digestionSystem.units.filter(function (unit) {
 					return unit.alpha === digestionSystem.unitFullAlpha;
 				});
-				if (fullUnits.length < digestionSystem.maxUnits) {
+				if (fullUnits.length < digestionSystem.maxUnits && digestionSystem.units[fullUnits.length]) {
 					digestionSystem.units[fullUnits.length].alpha = digestionSystem.unitFullAlpha;
 				} else {
 					// Game over if the Digestion System is full
 					LK.showGameOver();