The art and character concept are cute. The gameplay is pretty smooth. It would be nice if there was a bit more clarity somewhere that to complete a level you need to collect enough Yolkium and purchase the "upgrade" of advancing to the next map before time runs out. Possibly also make that "upgrade" be a different color, or have a border denoting it as different.
I played through on easy and normal, then did one map on torment just to see the difference. It feels like it gets easier as you go, since you can have upgrades, and there are more of the larger ore clusters. There should probably be some added challenges on later difficulties, such as tougher blocks requiring more power to break through, or hazards to avoid.
It would also be nice if the clickable area for the upgrades was a bit taller. There were a few times I was trying to rush and missed.
Overall, this was a cute and fun little game.