
I work in flash/flex, and I have some little games in my game development history. But, I want to turn on developing for facebook. I searched over the Internet for few days with hope that I will find some inspirating post/picture for my game. And I found this: http://theoatmeal.com/comics/pets_war
So, my game will be something like "Animals vs Humans" where animals after many many years of human terror decided to start a war against humans. Animals have many different kinds of weapons (mices will be regular soldiers, dogs will be heavy weapon etc.). But I have a little problem. What kind of game will be my game? It's have to be casual, and simple (becouse my market will be facebook), it must have some archivments, levels, and some estetic parts (or special war units) that players will buy for a real money. Is it the best options to be, like, I don't know "Angry Birds" based game? Or like "Plants vs Zombies"? Or something else? Pleas help me, I'm really stuck. I will be very grateful for any kind of ideas.
P.S. My english is not very good but I think that you will understand what is my problem. If you can't understend what I talking about, just ask, I'll try to simplify

Cheers