Finally got to play through this game and had a lot of fun! It didn't seem like the esc button to go to the next level worked once i was in the museum though, since I seemed to be stuck on that screen while I was there, but even a single level was plenty of fun.
I enjoyed just reading about the game before playing to go 'mhmm, that matches a bit with my game, oh yeah, and that part, oh and that.' But also seeing what was different was nice too. Just, the whole concept of a mining for fossils game and seeing the different ways we took it.
I know i got a tiny bit stressed from the timer, but i'm always like that when there's a timer, but I think part of it was not knowing I didn't need to dig up the entire fossil. I think part of it was A: going off needing to do so in my own game and B: I found the star leaf fossil first and being able to dig it up all the way and thinking 'ah, everything will be this size' and being wrong.
As for feedback, the sledgehammer seems very easy to overswing and break a lot of fossils below, even if it's the very first thing you do. The contrast of the dirt is sometimes a bit hard to see when it's the lighter variety on top of the fossils and you haven't quite cleared it. I know there was once or twice i wasted some time debating if something was a crack or some leftover dirt or just the art of the fossil itself and wondering if i try chipping away at dirt that may or may not be there and risk instead cracking the fossil.
You also mention a ground penetration radar map in the description, and if you don't just mean the map itself, I'm not sure how to activate the radar since you don't mention what button activates it. And I kinda already mentioned esc not working in the museum, but it's not that bad. if it weren't for the mention of it in the description, I would have thought there was enough to the game already!