I recently got back into playing this game with a few friends.
During Beta, this game had massive potential and a fairly active user base. There was always people playing and the servers were plentiful.
It's a simple beat'em'up platformer with a variety of weapons and a fun cast of characters with interesting abilities. The menu system is a particular high point for me, it's fluid and satisfying to use. The game is fairly fast paced, and I found it an absolute barrel of laughs. I have very little to say negatively towards this game, bar the contents next paragraph.
UNFORTUNATELY (And this is the reason for my recommendation): The game is dead. There is, on occasion, one active server within a 300 ping radius of my location, but it's a rare thing. If you can rally up a few friends who also have it, it revs back into action as the lively and entertaining beast that it should have been, but these sessions tend to be few and far between, and are, disappointingly, not worth the purchase.