This is a lot of fun, I really like that a mis-click only slows you down instead of causing the game to stop like in most Minesweeper clones. One simple suggestion: have the correct click sound more different to the incorrect click one, I kept getting an unpleasant jolt of "oh no I broke a fossil!" when I hadn't.
Interesting. The sounds are placeholder for this prototype, but I feel like I'd use a similar approach in a "full version" of this. The smash sound uses the dig sound, but there's a secondary, longer sound that continues afterward - do you feel like that's getting lost, or do you feel like having them both start the same is what's giving the wrong impression here?