This game deserves 4 stars simply becuse it put the 360 on the map. It is a bit of a Marmite game though in that some people (including myself) aren't huge fans.
For me the gameplay is a bit clunky and the main character is just an oafish thing that moves with all the grace of a hippo.
The other thing I don't like is that enemies take whole clips of ammo to kill and often even then don't die after that.
I did finish the game and found the story entertaining but it was met with more frustration than anything.
Due to my dislike of the game engine I found multiplayer just as bad. It seemed to have no real objective and (like Halo) to win it just required a skill of being able to run up to people and Melee.
It is a fantastic game, a brilliant concept and a true gem for the console but not for me.
You really have to give it a try though as you won't know if you like it until you play it.