To start with, this game looks good, feeling enough like a Gameboy game, and feels decent to control. I also like the idea of gold being required to meet quota to progress and its amount reduces your total amount. The slime girl is cute too.
I just think it could've been more challenging because there's not much of a fail state here, let alone hazards. For example, there could have been a time limit where you have to meet quota before then. I also think artefacts would be better optional collectables if they had a deeper purpose (like different endings depending on how many collected).
What we have now isn't bad per-say, but it feels quite repetitive and easy. I fully upgraded my shovel on Day 2 and I met every quota easily due to the abundance of gold you can collect. There also could have been background music to give the game more life.
Decent entry overall with a good concept that could be better fleshed out. Good work, anyway.