I'm really enjoying this game so far. I'm not quite done yet, but I'm having to take a break because of the one thing that I've found frustrating about the game: I have to retrace my path every time I need to back up to the surface. It would be really great if there was some sort of return to the surface command. As someone else mentioned, just have the bot follow the shortest path up, or have a teleportation upgrade that costs certain amounts of energy based on how deep you are.
I think that this would bother me less if the game moved a little bit faster... Though that may just be my slow computer. Overall, great game, and I love the way that it works. The fact that I'm improving the town by destabilizing the ground under it sort of amuses me, but I've been having fun with it.
Slight bug on level 15. There is a magically appearing block that makes it impossible to win even if you do the puzzle correctly.
No strong feelings on the game itself, but I play Match 3s to give me something to do with my hands while I have writers block.
 "Utopian Mining"){kind=icon}
 "Match-3 Puzzle"){kind=icon}