This remains a co-op favorite -- every year I'll gather together with two of my friends and we'll do an all-nighter through the game, each playing as one of the three different classes. The game is an insane amount of fun in co-op play - even after we cram too much crap into the elevator to the point of crashing the game between level loads and having to move everything out until we find which object is causing the problem.
With this update finally hitting release form, we'll have another reason to play it again! Definitely looking forward to trying this.