This was a lot of fun, I wish only you had included a timer at the end of the game so that this could be replayed and speedrun. I did a few runs to get the feel of it and it was so much fun. I could see how this could become its own game as the gameplay loop is so satisfying. the big monster at the end was a lot of fun but got stuck on a wall.
The game wasn't very different from a doom clone however and didn't add do anything for the theme integration so I had to drop points fo rthat. I wish there were more "traps" like the lava, requiring finer maneuvering through the level.
Great game, and follows a simple formula that's been proven again and again for being a successful format.