0h game jam! Make a game in zero hours!

I also built something, live on the IGG Marathon stream, no less:
http://twinbeardstudios.com/the-kid-and-the-kid-teal-alert

What went right:
- Asymmetrical co-op (one player uses arrow keys, the other the mouse)
- Grabbing Shamayel to do a couple of balance passes in the last few minutes of development.
- ASCII art looks stylish and is quick to produce.
- Using a solid framework. (The preloader is part of the framework; I certainly didn't build that in 0 hours.)

What went wrong:
- Blue player hard to see against teal background.
- Player bullets look the same as enemy bullets.
- Unclear when stunned.
- Unclear that it's co-op; when presented with the game cold, players try to shoot each other.
- Bugs.