Cast into the shadows by Doom and Doom 2, Rise of the Triad is a great game that many missed.
The only part that Doom is more superior in is the fact that it has more than 90 degrees walls. RotT was built on a heavily modified Wolfenstein 3D engine, and otherwise was stellar.
The graphics are far better than Doom's with actual people modeled. The sound is great and so is the gameplay. But the game is chuck full of easter eggs making it a blast.