Initial impressions based off a few solo-session play-throughs last night...
1. I feel naked! Having your agent be dropped off in the middle of a battle is a very different experience than from CD1...and I dig it. In the first Crackdown, rare was the time that you felt the pressure...that hopping and popping wasn't going to solve anything and everything. Don't get me wrong, it's still a hell of a ways away from the tension in a traditional shooter, but I do feel as though it's better. I also think this particular sensation was heightened by the fact that there was no Agency HQ to run back to (or, when necessary regenerate from). Never spent a ton of time in headquarters, but knowing it wasn't around definitely made me miss having the opportunity to visit.
2. Controls are...well...Crackdown! As I believe others have noted here, your agent feels a bit sluggish and his movements a tad too angular at the outset, but those feelings are, for the most part, erased after a bit of leveling. I like seeing the variety in melee being carried out on the screen, but as someone else here said, I liked the way it worked better in the first CD. Remember the problem from the first CD in which you'd lock-on to enemies in the rear, ignoring more immediate threats up front? It's ba-ack!
None of this bugged me too much, though. You know what did? Magnetically locking on to ledges. I don't recall it being quite so obvious in the first game. Here, even if I'm seemingly a foot or so away, based on game-scale, I still end up making the grab. A tiny thing that probably bugged me far more than it should.
3. Visually, it's a mixed bag. Someone else here referenced the dirtiness of our city in this sequel, but oddly enough, I found it a bit more...sterile? Not sure if that's due to the art, or texture downgrade, or what...but there was a sense of liveliness to the first title that has not, at least for me, carried over here. Or perhaps that was their goal all along, in keeping with the one agent vs. everything dealio. Water is purty, agent looks good, everything else is more than acceptable...but not quite where I expected it.
4. Platforming is complete comfort food. This is what I enjoyed most from the first game...aside from just doing crazy, random shit. It's all right here, the same, yet different. This is what'll keep me going in this game world, and the small changes that have been made do not detract from my love for this stuff.
In summary, if you dug the first game, it's pretty easy for me to recommend this one. If you didn't, I don't see much here that's going to convince you that this is now the greatest thing since sliced bread. Just as most of us had already figured. If you haven't played yet and are nervous, I'd say don't be nervous...just keep your expectations in check and you'll dig it. My pre-order stands, and I can't wait until the full retail release.