Cool concept.  I feel like you could add some monsters/traps etc like others said, but I like the choice of do I mine more or do I leave, maybe multiple levels where your energy replenishes a bit every level so you need to consider if you're willing to save energy for the next level or do you go back and rest.

All in all really nice idea, good job!

Neat game - Like the risk and reward - well done

Not bad game with interesting idea, but I think the gameplay needs dynamics (like traps or monsters). I also like the "fog of war" in this game. With this mechanic, you can come up with many other interesting mechanics and events :)

Short but nice game overall, and the music really fits the vibe! Maybe could've put some obstacles or enemies here and there to make the gameplay more interesting, but still good job!