Multiplayer in GTA IV

Mode	Players	Objective
Free Mode	1-16	Go anywhere and do anything! Like single-player, except playing with your friends.
Deathmatch	2-16	Anything goes, you can use any tactics you like to kill off the competition. Confined to specific areas of Liberty City to keep the action intense.
Team Deathmatch	2-16 (up to 8 teams of two)	Same as above but in teams. The best thing - four of you in one car (or even a helicopter!), one with shotgun, two with uzi's, one with molotovs!
Race	1-16	Race to the finish through each checkpoint in order: If you take a wrong turn or mess up in some way, you can respawn your vehicle on the last checkpoint you passed. There is a large selection of races for cars, boats, and helicopters - you can choose laps and vehicle class/type. Race has two types of races: Free Race and Cannonball Run. Free Races are point-to-point races, where the first one to the finish wins. Cannonball Runs are races where you have to traverse several checkpoints in any way you can.
GTA Race	1-16	GTA Race is exactly the same as Race, except this time combat is added. You are able to take out opponents with any weapons you pick up along the way. You can also get out your vehicle and find another one.
Mafiya Work	2-8	Mafiya boss Petrovic has jobs for you, which he'll describe to you over the phone. Each job is like a simplified mission. You might have to pick up recruits for the firm or take out a target, or PLAY Magazine's favourite - find and then dispose of a dozen severed heads.
Team Mafiya Work	2-16 (up to 8 teams of two)	Same as above but this time you are in competition with another mafiya team for the same job. More tactical this time, and more challenging.
Cops N Crooks	4-16 (two teams)	One team plays the crooks, one the cops. One of the players on the crooks' team is randomly assigned the boss and the others have to protect him and get him to an escape location on the map, while the cops have to hunt and kill him. Like Race, this mode has two sub-modes: All for One and One for All. In All for One, one team is made up of Crooks and a Boss, and the other team is made up of Cops. The Cops are trying to hunt down and kill the Boss while the Crooks are trying to protect him. The Cops win by killing the Boss and the Crooks win by getting the Boss safely to the getaway vehicle and escaping. One for All is similar but there is no Boss. Here, the Cops win by killing all of the Crooks and the Crooks win by filling up a getaway vehicle with members of their team. Only 4 people can escape in the getaway vehicle. Players cannot respawn in this mode.
Hangman's NOOSE	2-4	This is a single player mission featuring co-op play. Mafiya boss Petrovic has illegally flown into Francis International Airport, and someone has tipped off NOOSE. You and your team must protect Petrovic and get him to a safe location in Liberty City, while being pursued by the Liberty City Police Department's NOOSE (SWAT) division.
Car Jack City	4-16	What Petrovic wants, Petrovic gets. Car Jack City pits you against everyone else in a race to nab vehicles for the all-powerful Russian Mafiya boss. The ends justify the means, so do whatever it takes to grab all the cars. Just like Team Car Jack City, the amount of money you have trumps the amount of cars you've delivered.
Team Car Jack City	2-8 teams	Cars spawn in random places on the map and the teams must steal them and take them to a drop off point. The cash teams get for dropping off stolen vehicles depends on their condition - teams get less cash the more damaged they are. There are exceptions though: some are special bonus cars, containing drugs, which give a set amount of cash on delivery no matter how damaged they are. Your crew has to get hold of whatever vehicles the boss wants. Whichever crew makes the most money wins.
Turf War	2 teams	A timed capture-the-base mode. There are a number of bases around the map that you have to take by standing near them for a short period of time. The more players that are on a base, the faster it can be captured. The more bases that your team owns, the faster your team's cash score increases. If the rival gang is on or near a base, you won't be able to take control of it. The team with the most cash at the end of the round wins.
Deal Breaker	2-4	Time to crash the party. You and your team will work together to bust in on a deal that's going down, take out anyone in attendance, grab the goods and wipe out the witnesses. Don't get busted, don't get killed, and walk away with a nice chunk of change.
Bomb da Base II	2-4	Bomb Da Base II tips its hat to Bomb da Base (from GTA3), one of the most outstanding Grand Theft Auto missions ever created. In Bomb da Base II, you and your cohorts will work in unison to sabotage a large cargo ship. Ample amounts of vehicle theft, police chases and gunfights are involved. Like HANGMAN's NOOSE, you can respawn up to three times before being dropped out of the mission.