Area 51 Defense

Area 51 Defense is a survival shooter seen from a bird's-eye perspective. You try to survive as long as you can, fighting against waves of zombie mutants, hulking aliens and crab-like monsters. There is a large collection of weapons and other power-ups you can pick up. In the game's editor you can place turrets, soldiers, enemy spawns and create entirely new playable scenarios. Although the game began its life as an early access title, it has received updates since its launch.