I swung by to give this a try, but sadly don't have java setup. As for updates: https://ldjam.com/events/ludum-dare/rules - official rules, here's the relvant snippet:
Additional Notes for both the Jam and Compo
Both events have a Submission Hour that takes place at the end of each event (48, 72 hours later). This is an extra 1 hour for you to package-up and submit your game. In the case of the Compo: After that 1 hour, submissions for Compo will close, and you will have to submit your entry to the Jam.
Porting (especially to Web or Windows) can happen after the initial 48 hours. The longer you wait though, the less time participants will have to play your game.
Certain Bug Fixes are allowed. You can’t add new features, but if something broke or didn’t work correctly as you were finishing up, you can fix this after the deadline. You are asked to highlight the changes you make in your submission (a short change log). You probably wont get a 2nd chance with some players, but at least it wont be a problem for future players.