im gonna tell you right now, its not easy, im pretty sure your WAYY better off doing it in a real 3D engine. i just did it to say, IT CAN BE DONE, but whoa it was hard. The models are made using custom event spawning code, they're not in any format, only my game can use them, the animation is really complicated to pull off, using beziers, nested loops, trig, and all kinds of stuff. Its all a big "trick" and you don't see whats really going on. The rotation and cameras alone are their own bag of worms. And wrapping textures using only distort maps is real tough
This is made BEFORE the 3D object came out, theres not one of em in the game, actually theres no 3D boxes either, everything 3D are Sprite objects.
I know that theres already an example of a Wolfenstein game on here, see what you can do with that.