Right now it seems that NOVA is the game to get. On the behalf of those who've haven't bought it (including myself) why is it so great? Is it really as good as everybody says it is? To me it looks exactly like any plain old fps on the iphone. What separates this game from the other fps? Can somebody generously explain to me the pros and cons of this game in more than a phrase like "It's good because it's good"? Thanks!