Anvil Software is a freeware developer that has produced several first-person shooters made in GameMaker inspired by Wolfenstein 3D. Originally released on the now defunct YoYoGames Showcase, they have since been uploaded onto GameJolt.
Tower of Anvilstein 3D
A seven level first-person shooter.
Link: https://gamejolt.com/games/tower-of-anvilstein-3d/40685
Mace of Fate
Sequel to Tower of Anvilstein 3D.
Link: https://gamejolt.com/games/tower-of-anvilstein-3d/40685
Castle Totenschloss
Third game in the series.
Link: https://gamejolt.com/games/castle-totenschloss/40694
Rise of the Iron Knights
Fourth game in the series.
Link: https://gamejolt.com/games/rise-of-the-iron-knights/42882
Fuchsenstein 3D
Remake/reboot of the series.
Link: https://gamejolt.com/games/fuchs3d/382114