Developers must make hard decisions with sequels, especially on new consoles. Rockstar's emphasis on gritty realism, relationships, and a distinctly New York-inspired version of Liberty City is bolstered by substantially better physics and animation, which takes the series from looking kiddy and arcade-like to characters who display believable eye movement, realistic facial features, and realistic rather than robotic movement.
The new art direction, investment in physics technology, and better animation sum up to a huge aestehic improvement over previous games, giving GTA IV a level of visual appeal it strained for in the previous generation.
Pros: Great story and character development; player choices and friendships invest gamer like an RPG; solid multiplayer additions.
Cons: Fundamental gameplay doesn't add much to genre; interaction with basic objects can be a chore; online games kick you out to single-player game.