Is it OK to update our games after submission, but before the Jam period ends? 

I will admit that I've already made one update to fix a few bugs that were kindly discovered by another participant, and another had a great idea I'd like to incorporate before time is up.

I don't see anything prohibiting it in the rules, but wanted to make sure...I guess I could rollback the bugfixes if needed :)

You can definitely update your projects, all the way up to submission time! In fact, I'd highly encourage it.

Woot! Thanks for the lightning fast reply!!