This is the multiplayer portion of the game only!

Full Disclosure:

This key was obtained for free, using the method described here:
http://www.steamgamesales.com/view-comments.php?id=5033

Keys obtained using this method are completely legitimate and legal. You can get one yourself by following the instructions above, but it takes a bit of time and a lot fiddling with proxies to get it to work. I got two keys, so I decided to give one of them away, to save someone the trouble of going through the process themselves! Enjoy!