Bulletstorm removed from Steam -- But why?

Epic Games' 2011 first-person shooter Bulletstorm is no longer available on Steam, vanishing from Valve's PC marketplace earlier this week. That's what we do know. What we don't know is why. We have reached out to Epic Games for comment, but have not heard back yet. Bulletstorm remains available for purchase via EA's Origin download platform. You can buy the game there today for $20. Developed by Epic Games and People Can Fly (now called Epic Games Poland), Bulletstorm launched in March 2011. De...