Thanks for playing and congrats on reaching the end! As far as I can tell you're the 2nd person to make it that far, well done!
There is no exit in the Breeding Grounds, that's the final level as of now. It seems you missed the secret level you can access in the Burrows, which leads you to the Skeleton Pit dungeon. No exit there, just a Golden Goblin as a reward at the end.
Everything after the Halls of Pain I consider to be super unpolished - my goal is to now start on Lower Dungeons 2 and make my way up slowly. I'm glad you like the Faceless! I had a lot of fun making those.
As for choke points, I think in general I made a mistake by having some large enemies early on which then necessitated large doors. I think I'll fix this as the game progresses, at which point choke points will be a bit more important anyway.
The Phasmids spam a -Defense debuff on you, that's why the Bugmen tend to land hits so often!
Thanks again for the detailed feedback and for playing the game all the way through. It makes me glad people are enjoying their adventures