The feedback on the mining action is spot on! The sound effect, the subtle screen shake, even the selection box shakes a bit. Definitely a satisfying mining experience.
The goal of the game is a bit vague, simply "get better upgrades" doesn't attract players to pursue. I suggest adding some milestones as short term goals (like a quest), like how deep the player has gotten, how many gems they've obtained, etc.
Good job on the game!