"Certainly, Liberty City in "GTA IV" will look much more familiar to New York City residents than "GTA III's" rendition of Liberty City. Developers painstakingly created a virtual representation of New York City in this game. Newly renamed areas represent each of the five boroughs, save Staten Island, which developers felt would not be an interesting enough locale. In its place is a fifth area, called Alderney, which stands in for New Jersey.
Not only is the entire map much more interactive and worth exploring, but the detail level of the environments is incredible. The rising and setting of the sun not only casts shadows, but also reflects off glass and lights up details of buildings. The streets are marked with potholes and rubble and these terrain alterations affect the way that characters walk over them.