This game is crazy fun. no way this is your first game jam. i am genuinely addicted. I have created a beast of a miner when i finished playing one shotting gold and mining at light speed.
But my big issue, Now I was already one shotting gold ore so now ofcourse the next goal is to one shot diamond ore. but i saw a portal and went in and game finished... I was kinda sad. The goal should be creating the best miner with the best upgrades, not finding some portal to end all your progress. Maybe instead of findinga portal to beat the game, it could be this impossible hard to mine ruby ore which you can grind and get your upgrades to mine that ore. So the replayability may come from how fast and efficiently you can find and mine that ruby ore.
But overall the most fun game in the jam!