Just downloaded the PC ver. It's so unique that it's freaking awesome.

EDIT: I just fucking decapitated someone.

 

It's been out for a long time as a pretty well-known freeware game. If you really wanna know what it's like...just play it, lol.

If I had to describe it, I'd call it an anatomically-based, ragdoll-physics fighter...if that makes any sense. Basically, you control a guy, but instead of just pushing a button to punch, and another to kick, you need to adjust the joints of your character in order for him to move appropriately. It's really hard to even successfully punch someone when you're starting off, but over time you'll get a feel on how you need to move your character to do crazier things. Heck, some of the more experienced players fight exclusively using their feet while standing on their hands.