Fiddy deserves better, GAMERS deserve better.
What bothered me the most was the controls, it's very difficult to kill enemies. The AI is very dumb, but they're plentiful and they run around and can take a lot of damage. That coupled with the fact that it's very tough to aim, makes for a challenging game. You also have this thing called "counter kills", apparently you just walk up to enemies and press X to kill the enemies instantly. Sometimes this work, other times it doesn't. I do NOT advise you to just run up to an enemy, because it may not work.
Each level usually ends with a boss fight, these are just like regular enemies, only they can take even more damage. The game ends with one of the easiest boss fights in history. Voice acting is appropriately cheesy, Eminem gives the best performance as a shady cop.
Graphics are a mixed bag, characters, and mainly the G-Unit look good, levels look bland and dull. I noticed several glitches during the game, some were very funny I must admit. Invisible walls also pop in every now and then. The music...look, if you like 50 Cent there's a lot, no I mean a LOT of tracks and music videos and cool extras for you to unlock.
If you really like 50 Cent, you could check it out, maybe give it a rental. It's a straight-forward third person shooter, it's nothing special or unique about it. You may want to wait on 50 Cent: Blood on the Sand, which looks a lot better.