I made a small battle game, you control a square and use awkward keys to jump around, kill other players by jumping on top of them.
Z: Move left
X: Move right
R: Change costume
Sword: Kill people by walking into them
Shield: Block sword attacks
Players were supposed to be blobs which can expand (by pressing Z+X), causing them to bounce up, but that looked lame. Players could also wallrun, but that made controls too confusing.