The concept is pretty cool and the graphics are pretty awesome. The only downside I'd mention is the drop rate—there have been runs where I didn't encounter a single enemy before I could replenish my health, so I'd often die and didn't have a chance to get very far.
It's an interesting idea, although the only downside I see is that overusing the same mechanic (relying on probability and luck) both to earn rewards and to get upgrades can make it a bit boring after a while and too dependent on luck. Other than that, it's actually pretty good.
It's pretty entertaining; I find the gameplay interesting. To be honest, it's a game that can really hold its own if you keep adding levels gradually and throw in some varied challenges.
