Thank you very much for testing and the feedback! I'll try to answer the questions as I can.
Indeed there is no dungeon heart. My plans are to have fights happen outside the dungeon, and if the entrance should ever be discovered, the player must relocate the dungeon. I never liked the idea to fight another keeper in the original, so in Imp City the player will get options to send creatures to raids and expeditions on the upper world. This is currently incomplete in the code, and deactivated in the releases, and also there are some open detail questions on exactly how such an expedition or raid shall happen - fully automatic, or with player interaction? I'm undecided yet, but I think I'll activate the fully automatic version soon, so that people at least get an impression what the actual game will be about. Raiding the upper world for rare artifacts and valuable treasures. I might still add a sort of shrine or something as heart, where creatures check in and out if they quit service for you.
An overview map is a good idea. I'll add that to my to do list.
The feature to possess minions and act through their hands is interesting but out of reach for my coding and graphics skills. Very unlikely to come, due to that.
Creature list, general statistics. Missing indeed. Will come later.
The time aspect is mostly for the expeditions and raids. They will take time, so while the party is away you have less workforce in the dungeon, and if they should be overdue, you can assume something went wrong. So the player needs to know the time and when to expect a party back.
Imps can stuck due to a number of reasons (creatures likely too). I hope to identify the conditions and fix the problems step by step. Right now I can only confirm, yes one can trap imps by confusing their AI. Their pathfinding might be less than perfect too.
The performance problems might be related to this. If creatures cannot find a path, they try again and again, and depending on circumstances this can really eat a lot of CPU power. Also a thing I must look into. In general I want this game to run on low end computers and even system like a Raspberry PI 3.
And yes, the camera has a problem. Dragging only works properly if you hold the mouse still, press and then move. Pressing the button while moving the mouse confuses my code. Definitely a bug which I must fix.
The screenshot seems to show a problem that slipped into the v0.19. Imps are too "thick" in terms of pathfinding to pass through the gaps between the alchemist equipment. They can't get to the block in the middle or the ore mound at the bottom. It's fixed meanwhile.
Thanks again for the test and the feedback!