The possess creature was in the first game. Have you tried the original with keeperFX? It improves the UX for building rooms so if that was your issue with the first game.

That feature was a "you're kidding!" moment for me when I first played that game. Ok, the first person graphics weren't exactly Doom, but that they were there at all was crazy. First person shooters were a pretty new genre when the game came out! They even were "better" than Doom in some ways, with many monsters having ridiculous graphics filters.