The graphics is simple, but the gameplay is nice.
I like the use of different tiers of pickable item as currency to the next tier, and the number of item spawn depended on their level. Pretty cool idea.
But the process is a bit too slow after the third tier, and it could be better is there are sound.
Also the autopicker hand at the bottom will stuck at the left corner for some reason, maybe its a bug?
Anyways, nice game!