Created by Mattykins for OMGJAM3 (create a game in 48 hours) this is a nice little shoot-em-up that takes place in a rotating world.
"Play as an alien bounty hunter. Kill all the enemies in a given wave to progress, and buy upgrades in between waves. Survive for as long as you can.
Arrow keys or WASD to move, spacebar to shoot"
As usual the full source code available.