noonat's Refuge is sort of a physics-based Missile Command game created for the recent Ludum Dare competition, where players have to defend their city from an alien invasion with the help of a turret that fires only one bullet at a time. Luckily for you, any alien that is incapacitated by your shots will also knock out all other invaders that it touches on the way down.

The game ends when there are no buildings left standing in the city, although you do get a chance to submit your score online as a consolation for the humiliating defeat.