A really nice time killer but to big a map for to short a game. You can finish all quests in less of a quarter of the actual map size. And how about some little things to make the underground more exiting? Maybe an underground lake you have to be carefull drilling around because it would destroy your tunnels below and take a big part of the villages water suply. Or a flood from the beach and you have to quickly drill the sand underneath away so the water cant rise to high...something like that.
I'm looking forward to Utopie Mining 2.0