Great work! The game is highly polished and feels great to look at and play. The mechanics are solid, the upgrades are good, and the overall atmosphere is great too.
That said, I feel like the game loop itself is a bit incomplete. It feels like there's something missing, a stronger hook or motivation to keep the player engaged over a longer period of time. I kept asking myself, "Why do I need to connect the drill's wires?"
One idea that came to mind is that the wires could carry oxygen to mining camps. You could have multiple camps, each with a different timer before their oxygen runs out, forcing the player to prioritize some camps over others. You could also add enemies that try to damage the oxygen supply, creating more urgency and giving the player a stronger reason to upgrade their equipment and defend the network. Of course, these are just my thoughts.
The background music also lost some of its charm after a while due to how often it repeated.
All in all, great work!