The graphics are cute. But i'd have to agree with everyone else about the paid content being a little silly. I'm sure no one would care if you had a webshop that sold t-shirts with the characters on them, or accepted donations...but yeah.
It works smoothly, but as others have said it is too easy. I can play the game without looking at the screen.
If there were some other enemies to kill, or if they shot things at you, that would be an improvement. Maybe have it so you can shoot health capsuls in the air or something so we can see how long we can last? That would be nice. Anyway keep it up!
I found this game to be very in depth. The mechanics, graphics, and overall gameplay was just amazing. There was structure throughout the game if you wanted it, yet you could stray from the regular path to create your own experience. 5/5 stars, but 10/5 if I could give it.