I have competed in and finished my first Ludum Dare Mini Competition. My entry is Pyloon, a Ballooning Simulator. It took me about a day, broken up with life concerns. I used python and pygame, which was a nice framework to use.

The competitions theme was constraints, and was governed by these constraints. It was fun and interesting to comply with them, though I would have preferred a bit more vertical room.

The game needs balancing. I agree with the comment that you should always be lifting or falling; some experimentation with staying level showed it to be a `killer' strategy. Testing requires more time than I thought it would---I will have to plan more for it next time.

All in all, worth it, even if my time was limited.