i played this game with my 7 yr old from beginning to end. its very easy for trophies (i think 10 popped within the first 5 minutes of playing), but the controls and 'combat' are terrible. the game gets very annoying very quickly.
The game is good for any trophy hunters that don't mind collecting a lot of items, but otherwise isn't good for much. It can be beaten in about six hours and platinumed in less than 12, and it does have 4 player local co op. It might be fun for a group of kids but otherwise its not very good.