Thanks! Things are definitely starting to move on this.
Stylistically, the first-person segments are more or less a continuation of my GZDoom-based games. The sprites and animations are similar to Tactical Weapons and Tactics, and some of the environments are reminiscent of my long-abandoned Ascension Revolution project. Obviously Doom and other shooters of the 90s were huge influences on those projects and on my games in general. Ken's Labyrinth and Catacomb 3D are names I haven't heard in a long time, and Quiver not at all, but yeah, I can see how it might remind one of some of the lesser known titles.