This was a lot of fun to play!
It definitely felt hectic at first trying to learn all the mechanics of the game while trying to survive, but maybe that was intended. The game is 2 years old but here are my comments anyways:
1) Hover-over tooltips for each element would be nice, or a small tutorial.
2) It's unclear at first which elements are clickable, perhaps have a yellow border around those buttons.
3) On the first screen, you could combine the stats for the bitcoin miner into one box so there is less clutter. For example the box could say:
Current: 0.003 B/click
Upgrade: + 0.001 B/click
Cost: $14
4) It appears the "saw+hammer" button and the "toolbox" button bring you to the same screen, so you only need one button.
5) In the toolbox screen, the two "L" shaped buttons seem unnecessary. Instead, if you click something to upgrade, there can be a confirmation screen to upgrade it, or simply double click.
6) For the stats at the top left. I'm assuming the star is your level? I don't think it affects anything (other than unlocking a button), also you can just name it LVL to make more sense.
7) The ATK and DEF stats aren't clear as to how much they help. I'm not sure how much better 4 ATK is than 2, for example. If the enemies were displayed when exploring the town, it may be more clear (to see how much I'm hurting them and how much my armor is helping defend).
8) The gameplay is at a really good level of difficulty at the beginning, constantly managing hunger and health. After a few bag upgrades, there is no real threat of dying. I maxed out the bag and sword, with a few points in the CPU and armor. 18 levels seems like quite a grind but could be useful if there was more content.
9) If you ever decided to add content, it would be cool if each area had different % chance of getting each item. Maybe one area has more tools but harder enemies. Visualizing enemy fights would be a big improvement.