Powered by Crytek's CryENGINE 2--the same technology used in Crysis and Crysis Warhead--the downloadable FPS offers eye-popping gameplay (seriously, watch the trailer) as players partake in its single- and multiplayer game modes.

Wondering what it's about? Here's a brief taste:

Having had your arm unwillingly detached from your body courtesy of a chainsaw, your new prototype biomechanical arm transforms into different twisted and brutal weaponry to aid you in the slaughter. Your goal: escape from the under city and free your brethren to take over the upper utopian empire to do with as you please.

The sale runs until March 24, at which point the game will go for $19.99.