Is there a theme?
You export the file to some platforms of your choice and you just click "Submit" where the join button is right now. :)
Hmm, maybe! I'm not sure though! The game must resemble around the not running out of resources. Maybe make it so that you don't run out of keys to open all the other doors. Maybe make it so that some of the keys spawn in some locked rooms. :)
You have to wait for the voting to end! Else you will get more downloads on your game. A.K.A. cheating!