some cool new features
Multiplayer
GTA IV will be the first game in the GTA series to include online multiplayer on a console[55] with goals of supporting up to 16 players and has been confirmed that multiplayer will be open-ended gameplay that allows players to explore the whole city.[56] Later revealed in an issue of PSM, GTA IV will have 15 modes of play and support up to 16 players,[57] with the player using a customisable character to play as, with a choice of gender, race and clothing. The modes of play include several varieties of deathmatch and racing, with a cooperative single player mission and free mode. Other multiplayer modes include Mafia, in which players try to complete an objective before their opponents, and Cops 'N' Crooks, in which one team of police officers must stop the other team of criminals from escaping. The map used in multiplayer will be the same as the single player map and the host of the games can control many variables like traffic, police reaction and laps in races. Rockstar has left one game type unknown and not explained some.
During a hands on preview with major review sites several new details were revealed. Gameplay in multiplayer is identical to the single player; players will be free to roam the map during multiplayer games, although weapons and spawn points will only appear within a pre-defined area. The host of the game has a great degree of control over the game and can specify where, when, and what weapons may be used, police presence and more. Voice chat is supported and the player may chat with individual players by calling them on the mobile phone.[58][59]
The online games are split into two types, ranked and unranked. The reward for the ranked gameplay will be cash. The amount of cash a player has will determine their rank.[60] The game does not feature any split-screen or LAN multiplayer modes[61].
Social Club
Main article: Rockstar Games Social Club
Rockstar Games Social Club is a web site that will display the gameplay statistics of registered users and feature competitions and awards based on player activity within the game.[62] The Social Club web site was announced on 27 March 2008 and launched on 17 April 2008.
The main features of the social club will launch on the same date of the game itself 29 April 2008. The Social club will also link with Rockstar's latest Midnight Club game, Midnight Club: Los Angeles.
The Social club will consist of multiple parts, initially including the LCPD Police Blotter, The Story Gang, The 100% Club, The Hall Of Fame, The Liberty City Marathon and The Zit.
Music downloads
Following a partnership between Rockstar Games and Amazon.com, players will be able to purchase real world MP3s through GTA IV's in-game mobile phone[63]. Players will be able to 'mark' radio songs that they like by dialing ZIT-555-0100 on Niko's phone. They will then receive a text message providing the name of the song and the artist. If a player is registered on Rockstar's 'Social Club' website he or she will also receive a real world e-mail with a link to an Amazon.com playlist where all of the player's marked songs will be listed and available to purchase.
Initially, this service will only be available in the US.