var Puff = Container.expand(function () {
	var self = Container.call(this);
	var puffGraphics = self.createAsset('puff', 'Puff effect', .5, .5);
	self.tick = function () {
		self.scale.x += 0.05;
		self.scale.y += 0.05;
		self.alpha -= 0.05;
		if (self.alpha <= 0) {
			self.destroy();
		}
	};
});
var ClickTarget = Container.expand(function () {
	var self = Container.call(this);
	var targetGraphics = self.createAsset('clickTarget', 'Click Target', 0.5, 0.5);
	targetGraphics.alpha = 0.4;
	self.x = 0;
	self.y = 0;
	self.setVisible = function (isVisible) {
		self.visible = isVisible;
	};
});
var HealthBar = Container.expand(function (maxHealth, currentHealth) {
	var self = Container.call(this);
	self.maxHealth = maxHealth;
	self.currentHealth = currentHealth;
	var background = self.createAsset('healthBarBackground', 'Health Bar Background', .5, 1);
	var foreground = self.createAsset('healthBarForeground', 'Health Bar Foreground', .5, 1);
	foreground.y -= 5;
	self.updateHealth = function (newHealth) {
		self.currentHealth = newHealth;
		var healthRatio = self.currentHealth / self.maxHealth;
		foreground.scale.x = healthRatio;
	};
});
var Hero = Container.expand(function () {
	var self = Container.call(this);
	self.findNearestZombie = function (zombies) {
		var nearestZombie = null;
		var nearestDistance = Infinity;
		for (var i = 0; i < zombies.length; i++) {
			var dx = zombies[i].x - self.x;
			var dy = zombies[i].y - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance < nearestDistance) {
				nearestZombie = zombies[i];
				nearestDistance = distance;
			}
		}
		return nearestZombie;
	};
	self.targetX = 2048 / 2;
	self.targetY = 2732 / 2;
	var heroShadow = self.createAsset('heroShadow', 'Hero Shadow', .5, .5);
	heroShadow.alpha = 0.3;
	heroShadow.zIndex = -1;
	self.addChild(heroShadow);
	var heroGraphics = self.createAsset('hero', 'Hero character', .4, .3);
	self.addChild(heroGraphics);
	var initialHeroRotation = -0.0872665 - 35 * (Math.PI / 180);
	heroGraphics.rotation = initialHeroRotation;
	self.healthBar = self.addChild(new HealthBar(100, 100));
	self.healthBar.y = -125;
	self.move = function () {
		if (self.targetX !== undefined && self.targetY !== undefined) {
			var dx = self.targetX - self.x;
			var dy = self.targetY - self.y;
			var distance = Math.sqrt(dx * dx + dy * dy);
			if (distance > 5) {
				var speed = 5;
				self.x += dx / distance * speed;
				self.y += dy / distance * speed;
				var angle = Math.atan2(dy, dx);
				heroGraphics.rotation = angle + initialHeroRotation;
				return false;
			} else {
				self.x = self.targetX;
				self.y = self.targetY;
				return true;
			}
		} else {
			return true;
		}
	};
	self.shootDelay = 0;
	self.shoot = function (zombies, bullets) {
		if (self.shootDelay <= 0 && self.targetX === self.x && self.targetY === self.y) {
			if (bullets.length === 0 || bullets[bullets.length - 1].hit || bullets[bullets.length - 1].x < 0 || bullets[bullets.length - 1].x > 2048 || bullets[bullets.length - 1].y < 0 || bullets[bullets.length - 1].y > 2732) {
				var nearestZombie = self.findNearestZombie(zombies);
				if (nearestZombie) {
					var dx = nearestZombie.x - self.x;
					var dy = nearestZombie.y - self.y;
					var direction = Math.atan2(dy, dx);
					var bullet = new Bullet(self, direction);
					self.shootDelay = 20;
					heroGraphics.rotation = direction + initialHeroRotation;
					return bullet;
				}
			}
		}
		self.shootDelay--;
		return null;
	};
});
var Zombie = Container.expand(function (hero) {
	var self = Container.call(this);
	var zombieGraphics = self.createAsset('zombie', 'Zombie character', .5, .5);
	zombieGraphics.rotation = -Math.PI / 2;
	self.target = hero;
	self.healthBar = self.addChild(new HealthBar(100, 100));
	self.healthBar.y = -125;
	self.spawn = function () {
		var side = Math.floor(Math.random() * 4);
		switch (side) {
			case 0:
				self.x = Math.random() * 2048;
				self.y = -50;
				break;
			case 1:
				self.x = 2048 + 50;
				self.y = Math.random() * 2732;
				break;
			case 2:
				self.x = Math.random() * 2048;
				self.y = 2732 + 50;
				break;
			case 3:
				self.x = -50;
				self.y = Math.random() * 2732;
				break;
		}
	};
	self.move = function (zombies) {
		var dx = self.target.x - self.x;
		var dy = self.target.y - self.y;
		var distance = Math.sqrt(dx * dx + dy * dy);
		if (distance > 0) {
			var speed = 3;
			self.x += dx / distance * speed;
			self.y += dy / distance * speed;
			var angle = Math.atan2(dy, dx);
			zombieGraphics.rotation = angle - Math.PI / 2;
		}
		for (var i = 0; i < zombies.length; i++) {
			if (zombies[i] !== self) {
				var dx2 = zombies[i].x - self.x;
				var dy2 = zombies[i].y - self.y;
				var distance2 = Math.sqrt(dx2 * dx2 + dy2 * dy2);
				if (distance2 < 1000) {
					self.x -= dx2 / distance2 * 1;
					self.y -= dy2 / distance2 * 1;
				}
			}
		}
	};
	self.removed = false;
	self.merge = function (otherZombie) {
		if (otherZombie.removed) return false;
		var newMaxHealth = self.healthBar.maxHealth + otherZombie.healthBar.maxHealth;
		self.x = (self.x + otherZombie.x) / 2;
		self.y = (self.y + otherZombie.y) / 2;
		self.healthBar.maxHealth = newMaxHealth * 0.8;
		self.healthBar.updateHealth((self.healthBar.currentHealth + otherZombie.healthBar.currentHealth) * 0.8);
		self.scale.x = (self.scale.x + otherZombie.scale.x) / 2 * 1.2;
		self.scale.y = (self.scale.y + otherZombie.scale.y) / 2 * 1.2;
		otherZombie.removed = true;
		return true;
	};
	self.hit = function () {
		var newHealth = self.healthBar.currentHealth - 30;
		self.healthBar.updateHealth(newHealth);
		if (newHealth <= 0) return true;
	};
});
var Bullet = Container.expand(function (shooter, direction) {
	var self = Container.call(this);
	var bulletGraphics = self.createAsset('bullet', 'Bullet Graphics', .5, .5);
	self.speed = 30;
	self.x = shooter.x - Math.cos(direction - .5) * 55;
	self.y = shooter.y - Math.sin(direction - .5) * 55;
	self.direction = direction;
	self.hit = false;
	self.move = function () {
		self.x += Math.cos(self.direction) * self.speed;
		self.y += Math.sin(self.direction) * self.speed;
		bulletGraphics.rotation = self.direction + Math.PI / 2;
	};
});
var Game = Container.expand(function () {
	var self = Container.call(this);
	var background = self.createAsset('background', 'Game Background', .5, .5);
	background.x = 2048 / 2 - 80;
	background.y = 2732 / 2;
	background.alpha = .4;
	var hero, zombies = [], bullets = [], effects = [];
	var scoreTxt, timer, score = 0;
	hero = self.addChild(new Hero());
	hero.x = 2048 / 2;
	hero.y = 2732 / 2;
	scoreTxt = new Text2('0', {
		size: 120,
		fill: "#ffffff",
		font: 'Impact',
		dropShadow: true,
		dropShadowColor: '#000000',
		dropShadowBlur: 4,
		dropShadowAngle: Math.PI / 6,
		dropShadowDistance: 6
	});
	scoreTxt.anchor.set(.5, 0);
	LK.gui.topCenter.addChild(scoreTxt);
	LK.on('tick', function () {
		if (hero.move() && self.clickTarget) {
			self.clickTarget.setVisible(false);
		}
		if (hero.shootDelay <= 0) {
			var newBullet = hero.shoot(zombies, bullets);
			if (newBullet) {
				bullets.push(newBullet);
				self.addChildAt(newBullet, self.getChildIndex(hero));
			}
		}
		hero.shootDelay--;
		for (var i = 0; i < zombies.length; i++) {
			zombies[i].move(zombies);
		}
		for (var i = bullets.length - 1; i >= 0; i--) {
			bullets[i].move();
			if (bullets[i].x < 0 || bullets[i].x > 2048 || bullets[i].y < 0 || bullets[i].y > 2732) {
				bullets[i].destroy();
				bullets.splice(i, 1);
			}
		}
		for (var i = zombies.length - 1; i >= 0; i--) {
			for (var j = bullets.length - 1; j >= 0; j--) {
				if (bullets[j].intersects(zombies[i]) && !bullets[j].hit) {
					bullets[j].hit = true;
					if (zombies[i].hit()) {
						zombies[i].destroy();
						zombies.splice(i, 1);
						score++;
						scoreTxt.setText(score);
					}
					bullets[j].destroy();
					bullets.splice(j, 1);
				}
			}
		}
		for (var i = 0; i < zombies.length; i++) {
			if (hero.intersects(zombies[i])) {
				hero.healthBar.updateHealth(hero.healthBar.currentHealth - 0.5);
			}
		}
		for (var i = effects.length - 1; i >= 0; i--) {
			effects[i].tick();
			if (effects[i].alpha <= 0) {
				effects.splice(i, 1);
			}
		}
		if (isGameOver()) {
			LK.effects.flashScreen(0xff0000, 1000);
			LK.showGameOver();
		}
	});
	stage.on('down', function (obj) {
		var pos = obj.event.getLocalPosition(self);
		hero.targetX = pos.x;
		hero.targetY = pos.y;
		if (!self.clickTarget) {
			self.clickTarget = self.addChildAt(new ClickTarget(), self.getChildIndex(background) + 1);
		}
		self.clickTarget.x = pos.x;
		self.clickTarget.y = pos.y;
		self.clickTarget.setVisible(true);
	});
	var spawnInterval = 2100;
	timer = LK.setInterval(function () {
		for (var i = 0; i < 2; i++) {
			var zombie = new Zombie(hero);
			zombie.spawn();
			zombies.push(zombie);
			self.addChild(zombie);
		}
		spawnInterval = Math.max(300, spawnInterval - 20);
		LK.clearInterval(timer);
		timer = LK.setInterval(arguments.callee, spawnInterval);
	}, spawnInterval);
	function isGameOver() {
		return hero.healthBar.currentHealth <= 0;
	}
});

===================================================================
--- original.js
+++ change.js
@@ -166,9 +166,9 @@
 		otherZombie.removed = true;
 		return true;
 	};
 	self.hit = function () {
-		var newHealth = self.healthBar.currentHealth - 40;
+		var newHealth = self.healthBar.currentHealth - 30;
 		self.healthBar.updateHealth(newHealth);
 		if (newHealth <= 0) return true;
 	};
 });