This was really fun! It took me a few tries to figure out what I was supposed to do in the first level, but I got it eventually... it turns out you're on the heroes's side, so building monsters is exactly counterproductive for advancing through the game. In fact, a strategy I adopted was spawn traps in front of monsters to redirect them down corridors.
With that in mind, the monsters were very challenging, and it stress of paying your bills was also very exhilarating. I really only had trouble with the final level, which I had to restart a few times (which resets the money back to 100, incidentally, although it wasn't a huge deal).
Two small issues:
- One level spawned without any lights in one corridor, not sure if it was intended
- I don't fully understand the logic behind the quest givers, but it felt like an exploit to be able to build the 4th level one, and then immediately replace it by something else (with lower upkeep) while still getting the heroes spawned.
Here's my final level "victory screen" (it shows that there's no monsters eating up my utilities):