Alien war is a thrilling game with the concept of defense. You have to protect your castle with your upgradable guns and guided missiles from the invasion of alien troops. In each stage, you are supposed to destroy the invaders and earn as much gold as you can. alien war, tower defense, strategy game, castle defense, space invaders, upgrade, missiles, gold, gameplay, mobile game, shooting game, defense game, space, invasion, coins, level, strategy, tower, mobile gaming