Darwin's Odyssey is a top-down survival combat game built in 48 hours. It's educational because it teaches you about evolution with 100% scientific accuracy and also zombies.

To play: W, A, S and D to move. Point and click to attack. Press H for help at any time. Objective: kill zombies until you die.

I coded it all from scratch using Ruby and some help from the Gosu library[1]. I suck at pixel art, yet I managed to produce some not-bad sprites in Photoshop. I used bfxr[2] for the sound effects, and composed what little music there is myself in GarageBand.

There's even an online high scores table!

Please feel free to browse the source code and other downloads at GitHub[3].

I love Ludum Dare. It's so much work, but at the end of it I come out with something I'm tremendously proud of. Working hard on something and then seeing the fruits of your labour is profoundly beneficial for your self esteem.

[1] http://libgosu.org
[2] http://bfxr.net
[3] http://github.com/EddM/darwin