These incremental digging games are always relaxing to play through as long as the balance is done right. I think the first few upgrades were fine in terms of pacing, maybe could be slightly faster or have more smaller upgrades at a cheaper cost. The exponential scaling you had makes it hard to gauge progress since the numbers jump by 30x after a single upgrade. The last section didn't feel good because you could no longer upgrade your pickaxe strength at that point, so having to hit everything 2-3 times instead of 1-2 from the previous areas (with proper upgrades) slowed down progress a lot. I sped ran to the bottom in about 6 in-game days and I think I saw everything there was. The main things I couldn't tell while playing was how much each item was worth, how much could I store/how much room did I have left, and a better indication of taking damage. Overall, good job with making an incremental game with a sense of progression that didn't feel too slow.