SMG could be Super Mario Galaxy, Sarah Michelle Gellar or perhaps a submachinegun.
A look at reviews on something like
metacritic shows some variety to the opinions for this game, ranging from 'above average with some big problems' to 'flawless masterpiece'. The
Eurogamer review (7 out of 10) made a good case for the score they gave it and saying ultimately that for 360 owners it doesn't succeed in its concept as well as Crackdown. It's certainly still a game I'm interested in but it's entirely possible that the game has been hyped up to make it seem to be more than it is.