They've been working on it since before GTA IV and it shows.
The level of detail in dialogue, map design, and things to do is impressive. A lot of time has been put in to this game.
The graphics are quite good, and as this game has been in development for so damn long, you can let the fact that it is an old graphics engine slide. They've done such a good job with the old engine though; really taken it to its full potential, and it's refreshing to see. Smashed up cars and suspensions that still somehow drive, damaged helicopters that sputter out in mid air and then suddenly come back to life, and an all-round large sexy environment to play in.
The polish on the physics and handling engine for land, water, and air vehicles is awesome. (Exception: helicopters wobble too much for no reason.)
For the first time ever in the GTA series the city and landscape feels much more "alive"; AI are not just mechanical beings doing predictable and flawed movements and tasks like in past games. They can be very unpredictable, they are smarter, they actually go around doing things, and every random pedestrian on the street has emotions for you to toy with if you so desire (such as nudging them a few too many times, staring at them, pointing a combat rifle at them, saving them from their mugger, etc) to draw an interesting response (such as running, wanting to fight, swearing at you, or inviting an entire gang to come beat yo ass).
Cop chases are often intense and can be quite hard - I like that.
Guns pack a punch and are satisfying to use. However like all 3D GTA games, it is a fairly poor third person combat system. It works, and you can do fairly well with it, but it is still shit. Close encounters when you are not in 'hand-to-hand mode' are pathetically awkward. Rockstar really needs to just blatantly copy the fighting mechanics of the Uncharted games in many aspects.
Online is better than it has ever been, and I haven't explored it deeply enough yet, but apparently you can eventually start setting up bank heists with your friends and shit and whatnot. Online has quite a few problems right now, but overall it is addicting and fun. I often stay up rilleh late on GTA Online.
Lastly, you can drink booze and smoke weed in this game. That is all.
PS: I am a better getaway driver than Airbo.
