I decided to try what I could accomplish in terms of developing a game from scratch if I constrained the development time to a few hours. The original idea was to improvise a game during a 1,5 hour bus trip which was a bit unrealistic to be honest.

When I entered the bus I had no idea of what kind of game to create and when I left the bus I had a very generic arena shooter engine. After that I basically flipped the game mechanics around.

The game was finished in about 5 hours (most of which went into polishment) and it's at least pretty addictive. It might also be pretty easy to see that a certain developer has influenced both the development method and graphical style :)

Polonez can be downloaded here 
(Windows only, wine might work).
The music was made by Luke Thomas.