PyWeek is for having fun, but it is a challenge too... and your peers will play your game and try to provide useful feedback. I play almost all games, so having a smooth experience helps a lot!

Most common issues I've experienced playing/judging submissions are:

• Missing or incomplete documentation: how do I run the game? what are the requirements? what are the controls? Also please tag uploaded files stating the platform (eg, game_windows.zip), nobody likes downloading a big multi-MB file to find that it won't work in his/her system.
• Portability issues: be careful with case-sensitive file names, hardcoded slashes in paths, and be aware that not all operating systems will play mp3 files (consider using ogg instead!). Most of these are easy to fix and most judges will fix them, but it will affect your "production" score.
• Copyright and licensing: be as explicit as possible. Not all the art has to be original, but not including the license is against the rules. It may not affect your final score, but give credit where credit is due!
• Exotic requirements: OK, this is perhaps a personal thing. Most successful PyWeek games tend to stick to the basics, and I think that's part of their success. It's perfectly fine if you require an uncommon library, but try to explain and document the requirement the best you can. Judges will try their best to run your game, but high requirements will raise their expectations!