I'm playing the PS3 version. When I first started playing the game I thought the same as many others have ..."This game is a solid 9". I was looking at the aliasing, frame rates and filters and what not and trying to judge it on it's technical merits but after putting 15 hours into it I can confidently say that it deserves all the 10's it has received and if it was a Spinal Tap game it would be an 11.
R* has created an absolutely immersive experience that tops anything anyone has done before. The devil is in the details here. The radio stations, the vehicles, the dialogue from pedestrians, the physics, the lighting, the explosions, the scale of the city, the character development, the story, the multiplayer......the list goes on and on. Liberty City truly feels like a living, breathing city. Beat up a bum, he won't drop money. Beat up some one wearing nice clothes, you'll get some cash. Beat up some one that just used the ATM, you'll get MORE cash. Go to the posh area of town and you find NICE cars and well to do citizens. Travel under the subway and you'll find homeless people. Go to Cerveza and the population is predominantly Hispanic, speaking in their own dialect...and the same with all the other ethinically oriented areas. I bump into a guy walking out of the internet cafe and he says in a stereotypical nerd voice.."out of the way NOOB"
I tried to steal a bike from some Hell's Angels and they kicked my ass and stabbed me with knives. I jumped on the stage at the strip club and the bouncers reacted like they should and chased me out of the club. The houses and building are all different. The docks, the airport, the parks, the city, the stores, the alleys, the billboards...nothing is the same. There aren't many recycled parts, or at least you won't notice them. Simply amazing attention to detail here.
I am a self confessed whore when it comes to framerates and graphical hangups. GTAIV is not immune to a little bit of slowdown here and there, but it's simply nothing severe enough to detract from the masterpiece of coding that this game is. It IS the sum of all it's parts. To the people that don't think it deserves the 10's...I say spend some TIME in Liberty City and you may change your mind.