GTA IV has proper depiction of story, realism, physics, characters, dialogues, AI and gameplay. This is the one of the unique but heartouching and breathtaking storyline type games ever made.
This is the game that will make you normal, humorous, action-packed in first half, but serious, betrayed, emotional and vengeful in the second half.
But for some players, it lacked some features and fun like the previous GTA games and has a poor optimization for the PC port due to which some players can't play this game in 60 fps.
But despite this, GTA IV arguably one of the attention to detailed but realistic open world games of 2008.
In my opinion I'm giving a rating of 5 out 5 stars.