I spent about thirty minutes with the game Sunday night and came away thinking that this is pretty much the same game as the PS2 version, but with prettier (much prettier) graphics. Not much for first impressions, but that was my initial reaction.
I played several missions, and made it to 2.x% complete. Like I said not much time. One strange thing was that I had failed one mission; no idea which one. I do not mind failing, but I like to be told when I mess up. Figured I would start over on Monday night.
So Monday night I started over, and went a little farther. Had a date, went bowling, but did not do well. This time I had no failed missions and am just under 3% complete with the game.
The environments seem rather large, the variety of cars is nice, and there seems to be a lot of people on the streets. I have not played enough to notice if there are predictable traffic and pedestrian patterns. Same for the radio stations; have not heard the same music twice.
GTA is either something that you love or loathe. For me, I can get past all the language, violence (have not seen much yet), and general mayhem. The series is over the top, and certainly not for everyone. GTA IV looks to be more of the same, but for me, that is not really a bad thing.