1 commit :-D
no, seriously, i developed in repository 1, then created repository 2 with only the cleaned up source code and no history. As all the assets still in the history might break redistribution rules.
You should create a cleaned repo with no history that you submit to the jam. create a dev-repo, do all your stuff, and for submission create a new repo with a single commit, that only holds the submitted file version and nothing else.
in the dev repo i had roughly 50 commits until finished.