I have to say, this is one of these few games in a jam I see real potential in as a full game. There is already so much content it's almost hard to believe 1 person made this in only a week. Very impressive.
The game loop is already pretty good. The mining is fun and the decision between mining and attacking make for interesting gameplay. The only problems I see are enemies that can't reach the player because they get stuck. But even if they did, the game is still too easy. I maxed out everything in 10 minutes and then there was nothing left to do. The enemies were never really a challenge.
That being said I see a lot of potential here. It would be interesting to see a full game here. Well done!
The theme is a bit weak though imo. The different worlds don't feel very strange at all.