First impressions: Pretty fun game. At first glance it is similar to GTA3 where you can run around freely and jack cars and run over people and blow shit up. It's also got some fun superhero style gameplay, kinda like a weaker version of Super Jump in City of Heroes, and other games where you can pick up objects (even bodies of people you kill) and throw them. And Halo's shield regeneration. And Gears of War's left-trigger-to-aim-better concept, but enhanced for teh ease -- your left trigger locks onto a target, and you can use a thumb stick to selectively aim at his head, leg, arm, or body. The same aiming applies to vehicles too, so you can shoot out their tires.
I only played for an hour or two, but it seems pretty bad ass. I took out the first named guy in one of the gangs and picked up his fat corpse and threw it off the building. I jumped around from rooftop to rooftop collecting agility orbs for a skill up and completed one of the foot races. I also shot up one of the gangs enough that they sent out hit squads to take me out.
It's a little hard to read some of the text on my non-HD screen, and it's hard to tell the weapons apart especially when they are on the ground. It's also hard to pick the right target. I will sometimes lock onto a vehicle rather than the gang member standing beside it.