The Dark Mod is a Thief game without actually being a Thief game.
Rage excels at being a first-person shooter and features phenomenal gunplay but everything else about it falls into mediocrity.
Quake II is another excellent shooter from id Software and also completely unrelated to the original game, minus the name.
Doom is a rewarding and refreshing experience. The combat is fast and fluid with a sense of progression that keeps you addicted to the gameplay. While the multiplayer is nothing special, SnapMap should keep players coming back for years.
Wolfenstein: The New Order is an amazing shooter that does the series the justice with a great story, amazing gameplay, and superb voice acting. This installment breathes new life into the Wolfenstein series and is one of the best shooters of this generation.