Jazz Software is a freeware game developer which created numerous remakes or homages of various old school shooters within GameMaker. In contrast to most 3D games made with the tool, they are actually quite playable. They were uploaded to the now defunct YoYo Games Showcase but are still accessible via the Wayback Machine. Other games remade include Doom and Rise of the Triad.
Wolfenstein: Operation - Iron Knight
The Nazis are attempting to build mecha, aka Iron Knights.
Link: http://sandbox.yoyogames.com/games/187051-wolfenstein-3d---iron-knight
Wolfenstein: Confrontation
Link: http://sandbox.yoyogames.com/games/188460-wolfenstein-3d---confrontation
Wolfenstein: Spear of Destiny
Inspired by the original Spear of Destiny.
Link: http://sandbox.yoyogames.com/games/183860-wolfenstein-3d---spear-of-destiny
Wolfenstein: Return to Danger
Inspired by the original Return to Danger.
Link: http://sandbox.yoyogames.com/games/185436-wolfenstein-3d---return-to-danger
Castle Wolfenstein
Rather than a 3D shooter, this is a 2D shooting gallery game.
Link: http://sandbox.yoyogames.com/games/175919-castle-wolfenstein