Submission possible after deadline

It's currently possible to submit after the deadline by (I think) keeping the tab where you're filling out the form open until after submissions are closed. Hitting "save" then only records the game name though.

No files, tests, or entry points are identified in the issue. Start by reproducing the behavior with a form kept open past the deadline, then trace the save and submission handling; done means submissions opened before the deadline cannot be accepted after it while the relevant save behavior remains correct.

Written by the indexing model from the issue text.