4 friends trying to play, we have too much lag everytime we interact with each other. Really unplayable, anyone else? any fix?

what happened here?

In the hub world basement there's a three headed door with a snake key not like the others. Anyone figure this out yet?

Is it coop-only ? Steam page says there should be single player. Actualliy in demo: Pressing any key on gamepad -> second player spawns -> going to edge right of screen with gamepad player -> screen not scrolling, while first player far from edge There is no info on key bindings for keyboard, so I actually can't play it solo neither gamepad or keyboard Am i getting something wrong?...

is there a way to start the level because i have tried evrey key and can get it to start