Well, I had over 15 hours break, but I also have a bit of an Asteroids game happening. New asteroids come in every 10 seconds.
This wasn’t my initial idea, but it is much easier to code.

10 seconds was the only category I didn’t really want, and one of the few I -1ed. Still, it kinda fits.

Still need sounds, health/shields indicator, and a start screen.

If I do Ludum Dare next time, I think I might like to start with a bit more of an engine, it’ll let me do something more complicated or original because I wouldn’t be so worried about time. Improving my drawing skills could be a good idea too.
And, of course, actually having nothing else during the time of the event, if possible. Other commitments really do detract from actually making a game.