public void end() {
		running = false;
		for (BasicZombie zombie : basicZombieList) {
			zombie.die();
		}
		basicZombieList = new ArrayList<BasicZombie>();
		for (Bullet bullet : bulletList) {
			bullet.alive = false;
		}
		bulletList = new ArrayList<Bullet>();
		for (Missile missile : missileList) {
			missile.alive = false;
		}
		missileList = new ArrayList<Missile>();
		boss = null;
	}