I made a game a while ago for a different gamejam that I think I could  use to compete in this challenge, the limitations in the Rules seem to state as long as I have usage rights we're good (I made almost all the models and sounds in the other game, part of the reason I didn't finish it).  Would I be able to re-use code as well, or would I only be able to use stuff like models and music for the new game?

i think re-using code would be a bit too much but reusing models and sounds(as far as you made them) should be fine

:)