StickSkills says: Grand Theft Auto IV starts off so strong. You're introduced to Niko, a fairly likable character with a dark past, and his cousin Roman, a man who clearly likes to think he's more successful than he actually is, but remains endearing despite that. Niko wants a new life, one like Roman's--free of death and crime. Unfortunately for him, it's not to be, as Roman's life has its own paths into the underbelly of Liberty City.
This sets up the game wonderfully, and as you play, you forgive the fact that the shooting isn't all that great, climbing is clunky, moving Niko around is awkward and numerous other faults the core mechanics of the game have. You overlook those because the story hooks you, because Liberty City feels like a real place--a dense, populated, living city. Evidently, this seems to be the part that garnered the game such rave reviews. Whenever people talked about GTA IV, they always mentioned the amazing feeling of the city, never the actual gameplay.