I really want to like it, and this game has really good parts, though overall there are some issues that made me unable to continue enjoying. I'd love an updated version of this since the core is awesome!
The good parts: upgrading your drill with appending of parts, collecting resources that allow you to upgrade things, anything that can be automated (like hiring employees), the reputation and contract system if the contracts would be better tuned
The bad parts, imho:
The drill goes way to fast even when having merely the second type of drill, the drilling was fun at the start of the game when there were some actual manual tactics involved, but with just 1 automatic shovel and two older drills it goes so fast that it's nothing more than randomly spamming the mouse left and right to make it zig zag a bit and maybe get more stuff
The lighting upgrades are not useful if the drill goes so fast that you can't control it anyway
Too many buildings that you need to scroll in the UI for to do daily things. e.g. the recycle center requires using its UI manually every day, not fun, let it work automatically instead?
I'm getting way more garbage items than the recycle center could ever handle.
Gem cutting: unclear what to do, requires creating expensive items that disappear, it's not well enough explained why you want to do this rather than just sell the gem.
Unclear what the workshop is for and why you want spend resources to craft the items in there, it doesn't have help text like the others
Various other buildings: unclear why I'd want to use them, just too much stuff going on, unclear what gives benefits even when reading the help texts and not enough willpower to try it all out if it'll mean a daily repetitive building UI action like the recycle center is, I'd prefer if there would be more obvious and less different ways to use the metals and gems I collect, and more focus on the mining (but then with the miner not going too fast like now) rather than all these buildings (or let them all do things automatically instead). Note that the forge is fine, that was one of the first buildings that unlocked, is simple to use, shows clear benefit (sell stuff for more), and can be automated (though I didn't have enough money to try that yet), and obvously the mechanic and market are also fine
Unreadable font: it's a pixel font (that is fine), but different pixels are having different sizes. It could be a bit bigger too (on a 4K screen), maybe if those narrow pixels became full size like the others? The 1 looks like a 7. It's as if it's a pixel font rendered onto a differently scaled or misaligned pixel grid
The UIs of buildings regularly require using scrollbars, but they don't support the mouse scrollwheel. Would be more convenient if scrollwheel worked
Unlock things based on progress rather than days. You can quickly run 20 days anyway just to collect coal for a contract