Can also confirm that we were (and are) in awe and big fans of ID, Romero, Carmack, etc. (We prototyped but never released a PC FPS.)
Playing an FPS deathmatch head-to-head on Game Boys was as giddy and intense as you'd expect in 1992-3. Literally, it was head-to-head ... those cables weren't very long.
Before anyone runs off to buy an old cart or run an image on an emulator, set your expectations of FPS framerates realistically for a Z80 (or 65816) console in the early 1990s. CPUs were slow for matrix (or any) math, memory access was slow, buses were narrow, "graphics hardware" was optimal for side scrollers and tile-mapped character graphics with a few sprites. All of this worked against quickly rendering frames of 3D. We certainly couldn't use any textbook 3D graphics algorithms. It was all trickery and shortcuts but it worked. (The SNES was a bit better though we predated the FX chip which I think would have helped more.) The Game Boy version was amazing for its portability. I personally enjoyed our SNES version the most but it was back to single-screen two-player. Both were written single-handedly by a genius engineer named Robert Champagne who later went on to be Chief of Technology at Nintendo Software.