Grand Theft Auto IV is the ninth title and the fourth main game in one of the most successful and iconic series in the history of videogames, and it is also the first title for the seventh generation of consoles.
Following the tradition of the 3D transition of the series, GTA IV is entirely located in one of the three cities of the original GTA, Liberty City, but now in present time, and with an environment constructed much like GTA III but bigger and more detailed. Liberty City is a virtual city based heavily on New York, where the player's avatar, a Serbian ex-soldier called Niko Bellic, has to gain respect, welfare and power throughout the game. His main goal however is to offer services in exchange for information locate a few Serbians from his past who betrayed him.
Like in most GTA games, the rise to power of the mobster apprentice begins with parts of the whole map inaccessible. He starts in Broker (based on Brooklyn), and, in order to access the other three districts of the city (based on the other major boroughs of New York City), the player has to make progress in the storyline. To do this, GTA IV has the usual structure based on missions, but with the major difference that, this time, there is not a "mission state" which prevents Nico from doing anything else. In GTA IV, the player can engage in various missions at the same time, and even has free access to the non-mission features of the game while doing one.
Free roaming is also a defining feature of GTA games. Most of the usual elements of exploration and interaction with the city are included in GTA IV, but they have been enhanced regarding previous games. Niko can cause mayhem in the city, hijack cars, listen to radio stations, observe the behavior of the citizens, enter thematic buildings, work as vigilante, taxi driver, ambulance driver, and much more. But he can also watch television programs or connect to the Internet, look for criminals in the police department database from a police car, walk from the ground floor of a building to the very roof, observe the improved A.I. of the pedestrians, hire taxi cabs to go where he wants, use the mobile phone extensively (like as an event reminder, for example), hire a prostitute, go to a strip club, and a lot of other things.
In addition, this GTA game is one of the first games using the euphoria motion engine, an alternate middleware solution much like ragdoll physics which makes all people in the GTA IV world move realistically depending on the situation around them. For example, every time Niko enters a car, a different animation will be generated depending on his position relative to the car.
Some features may be missing (like no drivable airplanes in this case, except for a helicopter), while many others become more complex or are totally new, but, summarizing, GTA IV follows the evolution of the major titles in the series. That is, any new GTA game has more features, is more detailed and is technically improved. The most notable addition for this edition is multiplayer, the first time for the console versions. The same free-roaming environment is offered for up to 16 players in 15 modes. Certain modes narrow down the environment to make sure players remain somewhat in each other's vicinity.
Compared to the console releases, the windows release features high resolution graphics, customizable multiplayer for up to 32 players, a video editor to capture and edit in-game footage and the possibility to customize the radio station Independence FM with own songs.
