/**** 
* Classes
****/
var MoneyDisplay = Container.expand(function () {
	var self = Container.call(this);
	var moneyGraphics = self.attachAsset('money', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.amount = 0;
	self.updateDisplay = function () {
		var moneyText = new Text2(self.amount.toString(), {
			size: 150,
			fill: "#ffffff"
		});
		self.addChild(moneyText);
		moneyText.setText('Money: ' + self.amount);
	};
});
var ScoreDisplay = Container.expand(function () {
	var self = Container.call(this);
	self.score = 0;
	var scoreText = new Text2(self.score.toString(), {
		size: 150,
		fill: "#ffffff"
	});
	self.addChild(scoreText);
	self.updateDisplay = function () {
		scoreText.setText('Score: ' + self.score);
	};
});
var Arrow = Container.expand(function () {
	var self = Container.call(this);
	var arrowGraphics = self.attachAsset('arrow', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = 10;
	self.move = function () {
		self.y -= self.speed;
	};
	self.isOffScreen = function () {
		return self.y < -self.height;
	};
});
var Bow = Container.expand(function () {
	var self = Container.call(this);
	var bowGraphics = self.attachAsset('bow', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.shoot = function () {
		var arrow = new Arrow();
		arrow.x = self.x;
		arrow.y = self.y;
		game.addChild(arrow);
		arrows.push(arrow);
	};
});
var Target = Container.expand(function () {
	var self = Container.call(this);
	var targetGraphics = self.attachAsset('target', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.speed = Math.random() * 4 - 2;
	self.direction = Math.random() < 0.5 ? -1 : 1;
	self.move = function () {
		self.x += self.speed * self.direction;
		if (self.x < 100 || self.x > 1948) {
			self.direction *= -1;
		}
	};
	self.hitTest = function (arrow) {
		return self.intersects(arrow);
	};
});

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

/**** 
* Game Code
****/
var background = game.addChild(LK.getAsset('background', {
	x: 0,
	y: 0
}));
var moneyDisplay = new MoneyDisplay();
LK.gui.top.addChild(moneyDisplay);
moneyDisplay.x = 2048 / 2;
moneyDisplay.y = 50;
var scoreDisplay = new ScoreDisplay();
LK.gui.bottom.addChild(scoreDisplay);
scoreDisplay.x = 2048 / 2;
scoreDisplay.y = 2732 - 50;
var arrows = [];
var targets = [];
var bow = new Bow();
bow.x = 2048 / 2;
bow.y = 2732 - 200;
game.addChild(bow);
// Create targets
function createTargets() {
	for (var i = 0; i < 10; i++) {
		var target = new Target();
		target.x = 2048 / 11 * (i + 1);
		target.y = 200;
		game.addChild(target);
		targets.push(target);
	}
}
createTargets();
game.on('down', function (obj) {
	var pos = obj.event.getLocalPosition(game);
	bow.x = pos.x;
	bow.shoot();
});
LK.on('tick', function () {
	for (var i = arrows.length - 1; i >= 0; i--) {
		var arrow = arrows[i];
		arrow.move();
		if (arrow.isOffScreen()) {
			arrow.destroy();
			arrows.splice(i, 1);
		} else {
			for (var j = targets.length - 1; j >= 0; j--) {
				var target = targets[j];
				target.move();
				if (target.hitTest(arrow)) {
					arrow.destroy();
					arrows.splice(i, 1);
					target.destroy();
					targets.splice(j, 1);
					break;
				}
			}
		}
	}
	if (targets.length === 0) {
		createTargets();
	}
});

===================================================================
--- original.js
+++ change.js
@@ -62,8 +62,16 @@
 	var targetGraphics = self.attachAsset('target', {
 		anchorX: 0.5,
 		anchorY: 0.5
 	});
+	self.speed = Math.random() * 4 - 2;
+	self.direction = Math.random() < 0.5 ? -1 : 1;
+	self.move = function () {
+		self.x += self.speed * self.direction;
+		if (self.x < 100 || self.x > 1948) {
+			self.direction *= -1;
+		}
+	};
 	self.hitTest = function (arrow) {
 		return self.intersects(arrow);
 	};
 });
@@ -121,8 +129,9 @@
 			arrows.splice(i, 1);
 		} else {
 			for (var j = targets.length - 1; j >= 0; j--) {
 				var target = targets[j];
+				target.move();
 				if (target.hitTest(arrow)) {
 					arrow.destroy();
 					arrows.splice(i, 1);
 					target.destroy();