public void onTick() {
		for (int i = 0; i < enemyList.size(); i++) {
			if (enemyList.get(i).onTick()) {
				lives -= Constants.enemyDamage[enemyList.get(i).enemyID];
				enemyList.remove(i);
				i--;
			}
		}
		
		for (Tower towerI : towers) {
            towerI.onTick();
		}
		
		for (int i = 0; i < projectileList.size(); i++) {
			if (projectileList.get(i).onTick()) {
				Screen.projectileList.remove(i);
				i--;
			}
		}
		
		for (int i = 0; i < particles.size(); i++) {
			if (particles.get(i).onTick()) {
				Screen.particles.remove(i);
				i--;
			}
		}
	}