From the Steam Store page:
Stick Fight is a physics-based couch/online fighting game where you battle it out as the iconic stick figures from the golden age of the internet. Fight it out against your friends or find random sticks from around the world!

2 to 4 PLAYERS in either Local or Online Multiplayer (NO SINGLE PLAYER MODE)
Physics-Based Combat System
100 Highly Interactive Levels
Level editor
Over 100,000 community made levels
Lots of weapons!
Procedural Animations using the system from Totally Accurate Battle Simulator