Defend the Earth

You are a veteran space force pilot. A unknown extraterrestrial civilization has just started invading Earth, and now the fate of mankind rests in your hands! Will they be stopped or succeed in their invasion?

Features:

• Campaign with 5 levels
• 4 difficulties (Easy, Normal, Hard and Nightmare)
• Destroy alien ships and asteroids to earn money
• 6 purchasable spaceships
• 4 purchasable upgrades

Controls:

• WASD/Arrow Keys to move
• Left Mouse Button/E to shoot