Ah forgot to add that after deciding not to have a 24 hour signup period.
Well for the sake of it, the 48 hours start with this post.

As for your other questions: The only guidelines about the game itself are that it has to be a fangame and that it has to relate to Jazz jackrabbit. How hard was that to comprehend? Which in turn answers DoubleGJ's question.

@Ironguy: Will the fangames be OMGTHISISMAKINGMYEYESBLEEDWITHJOYANDHANDSPRESSINGB UTTONSWITHPUREHAPPINES amazing? No. Do they have a chance to be halfway decent? Yes.