Descent: Journeys in the Dark is what got me involved in this hobby. I loved that game and wanted to play it all the time. Unfortunately, I couldn't always get a group together, so I endeavored to automate the Overlord. The result of those efforts would become the most popular (arguably) modification for that game, Descent Quest. It combined the combat of Descent with some of the game play of Warhammer Quest. I was pleasantly surprised at how people on TOS ate it up. And I periodically still get notes sent to me about it. That experience pushed me to create my own original games, and I'm still doing that today, with moderate success. I've had one game published, got a contract for a second game that never ended up coming out, and have a third game (co-designed with SuperflyTNT) coming out next year.
Fast forward to today, and I am releasing version 1 of Doom - Horde mode. This automates the Invader, and essentially lets up to 4 marines fight several waves of demons. It's pretty much non-stop combat for a few quick rounds. It is fun, and functional. I do want to express some caveats: this hasn't been thoroughly tested, which is one reason why I'm releasing it to the public as is, to get more eyeballs on it. You will likely die; tonight I ran a session in which two marines died in round 2. Don't expect a cerebral challenge that might be presented by a real flesh and blood Invader, but if you just want to throw some dice and blast some monsters, you could do worse.
I also highly suggest that you make the map in a circular manner; otherwise you will pretty much never leave the first chamber since you will be inundated with demons. Feel free to make suggestions or throw tomatoes.