The game isnt really over rated at all, there are new features in the game, actually there are a lot,
1. Better Graphics (Not a new thing actually but it needs at least to be noted)
2. Better Combat mode, with some more features in it (A little thing but isnt it the little things that makes it all great?)
3. Internet Cafe, Comedy Club, Other Clubs Around (Yeah in the old one there were some clubs but the social life in this game finally does something good)
4. Online Mode (Of course this is one of the things that is best, and because of the range of how much you can do this game rules for that)
5. New Physics Mode (You can do much more hang around things, even hang on a cars door, you can cover yourself to just about anything, and much more, when you are shot on parts, there will actually happen something and not just let you walk on, the same goes for the NPC´s oh and the way you die has also changed, there are just so many things to the physics department)
6. Mobile Phone, this thing makes the game more believeable, and there are tons of things you can do with the Phone, it makes the game become more real in every way)
7. A bigger Soundtrack (There are over 10 radio stations in the game, which is a great thing, more to listen to when you drive...´)
8. Downloadble content (The Xbox 360 has this and the PS3 will get this in 2008 fourth quarter so why bitch about that)
9. How you defeat affects a little of the storyline not much but this is still a little better, so if you do something it might change the end, which will mean there is a replay in the Main Story)
10. There is New York and New Jersey in this game, thats cool)
That was some of the new features in the game, there is more then these features, the game shouldnt be compared to SA they are just two differrent paralles, almost everything new in SA is also in GTA IV so what if some single Jetpacks, Tanks, and a little more isnt in it, they game has won, it is a game worthy and it surely deserves its 10/10 rating, stop comparing it to SA and start realising what the game has.
Oh Of course i know about the thing that there arent any planes in the game, but there are Helicopters so you can still fly around, thats cool, so stop bitching...
