I’m not sure where the line is drawn to say whether or not something is no longer using the engine of a game but I still find it amazing what can be done with old game engines. The universe of Doom modding is pretty vast with too much to cover although I have GzDoom and the Bloody Doom mod on my current gaming PC; I also enjoy Xonotic from time to time, which uses a heavily modified Quake engine. While the graphics look much closer to something modern, it still “feels” like the old games the mods were based on.
This mod called Total Chaos is the newest mod that can make your jaw drop, if you consider the foundation engine it is running on.
A few sounds gives this away but visually I would not have guessed that this runs on the Doom II engine. It has been in the works for several years and I don’t mind that it has stuff like 3D objects. I get a kick out of seeing stuff like this, I’m not sure why exactly, it is probably similar to where I love seeing an old piece of game hardware pushed beyond what people thought was possible.