Rule 4 says "All registrations and submissions are hidden until the voting window opens at which point all games will be available to play and vote on."
Last year this was not technically possible. The authors had to change the status of their game manually, close to the start of the voting period. There was no way the jam/organizer could reveal all the submissions at the same time. Unless this is now possible, I think rule 4 should be modified so it fits with what is actually possible. For instance, something like the game should remain hidden until 48 hours before the voting window opens or similar.