I'm undecided on whether this game is an 8 or 9 at the moment. Maybe by the time I get to the end of the review I'll have made my mind up
As far as sandbox games go this has been the most enjoyable one I've played in a long time. Probably the most enjoyable since GTA:Vice City, the others since just felt like one re-hash of the same thing too far.
I enjoyed the approach to story progression; very few missions; no annoying "travel to this part of the city now" moments; just a sprawling city filled with crime to fight wherever I turn. Story wise it reminded me of robo-cop from the off, which isn't a bad thing really, they kept the plot simple and largely out of the way of the action which isn't something I'm normally keen on, but for some reason I didn't really care when I was playign Crackdown. It was about jumping from rooftop to rooftop shooting rockets at gangsters in mid air, I didn't really care for the reason why
The rooftop races were well designed, probably more so than the street racing, which I thought was hampered by over populated streets, requiring you to mow down "innocent" civilians left right and centre to have any chance of making the grade.
The achievements were (generally) very well designed. The Orb hunter achievements were annoying as hell when I got down to the last few (still haven't got my last 5 Agility Orbs) but they kept me coming back to the city for another 10-15 minute blast, so did their job!
The Downloadable content was ingenious, and probably will push this game to a 9 for me. The Keys to the City mode was brilliant fun with a co-op partner and .. and ... and.
Time attacks seemed a bit pointless, most the battles could be completed in about 7 seconds by jumping right to the boss and firing a dozen rockets in his face, but the fun way was to blast the hell out of his personal army first -- which kind of comflicted with the time trial nature of the mode.
There's still too many good things to say about this game, but I'm already fearful of going on and on and on.
9 (Outstanding) - My favourite sandbox game of the past 5 years; i've seen nothing better since GTA: Vice City