Tripwire Interactive are celebrating their millionth copy sold with an 85% discount on Killing Floor during Steams 'Midweek Madness' deal period.
The game by itself will cost $2.99 and the game along with all DLC will set you back a whole $4.78. That's the cheapest the game has ever been sold at!
Killing Floor is a Co-op FPS similar to the popular Left 4 Dead series.
Find this deal here.