Duke Nukem Forever on PC uses Steamworks, developer Gearbox has announced.
"It means that regardless of where or how you buy Duke Nukem Forever on PC, your purchase will be tied to your Steam account, ensuring that you'll always be able to install a copy of the game even if you lose your disc," community manager Chris Faylor wrote on the Gearbox forum.
That's Valve's Steamworks, by the way - not the famous gay bathhouse in Edinburgh that Wikipedia picks out.
Using Steamworks means things like authentication services, peer-to-peer multiplayer, voice communications, matchmaking, Steam communities, friends, statistics and achievements are all taken care of.
But integrating Steam on a fundamental, irremovable level puts rival digital distributors' noses out of joint. Cue boycotts. In November 2009, Direct2Drive, GamesGate and Impulse all bravely refused to sell Call of Duty: Modern Warfare 2.
Obviously Valve was devastated. Oh no wait - delighted. Steam business director Jason Holtman said Modern Warfare 2 had become one of his service's best ever sellers.