well
the only reason i am giving you a zero is becasue you left out the two most important features in a game like this:
1. there is no save. i dont want to sit around playing 70 of the slowest levels ive ever encountered. if there was a save id come back to play.
2. a health bar for each individual creature. with no health bar i couldnt strtegicly upgrade and place weapons. if a creautre made it by my defenses, there was no way of knowing if he had a little health left or a lot. and the bosses, well after the first two the rest seemed indestructable.
i also encountered some glitches in the game which seemed quite bothersome, but other than that and my two reasons above this would have been a really addictive game. its a good and concept and good graphics but you cant forget the most important things. sorry but 0/0