Really liked this. The diverse use of textures really called back to ID1, but there was many small details that elevated it to a very light ID1+ style.
I enjoyed the gameplay for the most part, especially the final fight, but I feel as-if the fights in the areas leading up to each key could have been a tad more interesting. They're pretty much just hallways with monsters in them, which isn't entirely verboten, but having some route options and different types of rooms could have elevated things, as well as a better use of the height variation in the larger rooms.
The secret with the pent was a neat two-parter. Predictable, but I would be lying if I didn't like a lava bath.
Final fight was really well put together. I was rolling my eyes expecting a Chthon encounter, so when I got two vores to the face + a larger horde than the usual ID1 fare it gave me a good time.
Attached is my demo file, enjoy.