Back in the day—way back, like, when Duke Nukem Forever was conceived—free demos were often available before a game's retail release. These days, demos have all but disappeared from the landscape. Some developers offer up multiplayer betas long before a game's full release, but that practice seems to be more about fine-tuning balance and testing a game with a wide audience than giving prospective purchases a preview of the full experience.
Duke Nukem Forever showed its old-school roots by offering a pre-release demo, but only to folks who had pre-ordered the game or owned copies of Borderlands. Gearbox developed Borderlands and, as the studio that finally put the finishing touches on DNF, can probably be excused to trying to direct a little attention to its uniquely cel-shaded shooter/RPG hybrid. Fortunately, the Duke demo is now available free of charge to anyone with a Steam account.
Of course, the game has hardly received rave reviews, garnering a rating of 56 on Metacritic with a 6.0 user score. With a $50 street price, Duke Nukem Forever is probably a game you'll want to try before you buy. Thanks to Rock, Paper, Shotgun for the tip.