This game is very much like rock,paper,scissors. Though it adds depth through the use of cards and effects that can change outcomes for both your monster and your city.
Your job is to attack other citys to gain population while hopefully you make your city stronger by surviving other players attacks. Its a fun game with some crass off the cuff humour thrown in give it a try.
RayCanada about Monsters Ate My Metropolis, v1.01