Always love a little mining game where the game loop involves earning gold to get upgrades. I like the risk vs reward stability mechanic, especially as someone with a high risk appetite.
Unfortunately I think I accidentally spent all my gold on upgrades near the end and didn't have any left to buy another permit, LOL. I will try again and attempt to finish it later!
For some constructive feedback, I think the screenshake was a bit too much. Also, some more juicy feedback on breaking the blocks would have been nice, since that's the main thing the player would be doing. I would look at games like Core Keeper or even Minecraft for some inspo on that.
Other than that congrats on the game, and keep it up!