The graphics are improved and the enviroment interactions is great! More so than the previous GTA. Gotta pay toll roads if you don't wanna attract attention; drivers you carjack will try to get their vehicle back - even if it means hanging on to the door!; breaking car windows and hotwiring. There's just so much more to this game I'm sure I haven't discovered yet.
On a side note - I was driving my car really fast through the streets and came across an intersection at a red light that I just ran, but at that very moment an SUV, who had the right of way, was in front of me and plowed right into the side! It must've been the gas tank side because the SUV suddenly caught on fire; the driver got out on fire and *BOOM* the SUV exploded!
Oh. And you can get drunk at bars, and damn if it ain't hard to have Niko walk and drive! In fact, if you drink and drive, the 5-0 will be on the lookout for you and try to stop ya!
Highly recommended game - hands down!