It's still 1 ppl maximum...S1NT4X probably changes it to 4 so then he can play with his buddies...
No, actually I just set a million rooms up and made them never expire...
AMAZING gameplay :D
Tip for beating the first part: with all the blue (make sure you actually dodge and kill the purple guys later on, but) position your gun as close to a 45 degree angle to the top/right of the game, strafe (click and hold) and put the skull in the bottom left-most corner (as far as you can snug it in there). Let the blue guys come right to you - not one will hit you!