Content review for this game:
Pertaining to the ESRB rating.

Niko:
Main playable character. He's a former member of the Russian army and doesn't care if he lives or dies. Which means, if there's money in it, he also doesn't care who else lives or dies. For some reasons, Niko isn't keen on drugs or alcohol, but his constant, mindless murdering for money makes up for it.

Roman:
Niko's cousin. He loves gambling and women; both get him in loads of trouble. He's a coward, and doesn't go for confrontation. With this and his piled debts from gambling, he frequently in peril by shady characters—Niko has to save him several times.

Michelle:
Niko's first girlfriend in Libert City. You end up finding out she's an agent working for the government. Later in she introduces you to her boss; he'll give you some random bits of work in exchange for your freedom.

Little Jacob:
He's a Jamaican who can't stop smoking weed. As such, he mostly wants Niko to take care of drug dealers giving him, what he thinks, are bad deals. This, of course, means killing many, many dealers.

Vlad:
He's an obnoxious, loud-mouthed loser who has a small bit of power and acts like he owns the world. He'll mostly have Niko intimidate people who owe him money.

Faustin:
A man who loves to do cocaine and drink alcohol. He is extremely bad-tempered, and as such, has Niko kill, kill, kill people he doesn't like just for the heck of it.

Dimitri:
He's Faustin's old friend and assistant. He doesn't like how Faustin handles things, and tells him as much. He'll mostly be telling Niko to knock Faustin's orders down a notch. Later on, for complicated reasons, Dimitri becomes a major enemy to Niko.

Mr. Bulgarin:
Niko used to work for him, smuggling people across the Adriatic. On one mission, the ship sunk and Mr. Bulgarin blames Niko. This is one of the reasons Niko fled to Liberty City; to get away from him. But, it appears Mr. Bulgarin followed Niko there.

Brucie:
He's an idiot to the highest degree and loves to work out. He's often high on steroids and is the type of guy that says he does everything, but does nothing. He owns a car shop and mostly has Niko steal cars for him. But later on, the steroids get the best of him, and he then has Niko kill for little to no reason.

Manny:
He's the guy from the street that thinks he can fix the street, but really only wants to look good. He has a tv show that involves him "cleaning the streets," and mostly has Niko assist him in his goal by killing drug dealers.

Elizabeta:
She's a self-serving woman, who loves to party and do coke. She mostly has Niko get her drugs, or get rid of people who get in the way of said drugs.

Playboy X:
He's Elizabeta's friend. He will mostly have Niko help him get to, what he considers a higher standing in life, which involves killing people he doesn't like.

Francis:
He's a corrupt deputy police commissioner, who convinces himself that what he does is good, constantly reminding himself and others that he's a good person. He has Niko do "unofficial police business", or killing whoever is inconvenient in his eyes.

Packie:
He is Francis' younger brother, and is a little jerk who thinks he can do what he wants when he wants. He mostly has Niko do odd jobs, which involve things from stealing to killing (or both of the above at the same time).

Kate:
She is Packies sister, and Packie makes fun of her for being a virgin. Kate likes Niko, and a little after you meet Packie, you'll have the option of dating her from there on out. Kate is very involved in the game's two endings.

Dwayne:
Playboy X's old mentor, who just got out of prison. Dwayne lost all of his connections since he's been in the joint, and wants them back. He mostly has Niko help him regain some of these assets by killing those in possession of them.

U.L. Paper:
Karen's (otherwise known as Michelle) boss, who gives you missions that involve the government, in exchange for your freedom. He doesn't give his name.

Derrick:
He's Packie's other brother, who sleeps on park benches, doing drugs and/or drinking most of the day. He mostly has Niko kill certain people and steal; for erasing the past and what he says are "starting over" reasons.

Gerald:
He's Derricks younger and Packies older. He is a very hard, murderous guy who likes to drink. He mostly has Niko frame other mob factions to start mob wars, or later in, has him kidnap one of the mob leader's daughters.

Ray:
He's Packies friend, and a stereo-typical, Italian mafia character. Ray mostly has you do jobs like killing, smuggling, and stealing, involving diamonds.

Bernie:
(A.K.A Florian Cravic) was Niko's army buddy in Russia, and Niko thinks he is the one that betrayed him. Once he locates Florian, Niko finds this not to be the case. Florian now calls himself Bernie, is gay and sleeping with a married politician. He mostly has Niko help him keep his ties secret by killing whoever tries to leak it.

Darko Brevic:
He betrayed Niko and his friends in Russia, killing all but Niko for a thousand dollars. Finding Darko is one of Niko's main objectives throughout.

Bell:
Phil Bell is Ray's friend and a classic mob type. He mostly has Niko steal/sell drugs.

Gambetti:
He's an associate of U.L. Paper. Gambetti is an old man near death in the hospital. He wants the Russian mafia out of Liberty City, and mostly has Niko dispose of them and their dealings. He also helps you find Darko Brevic.

Pegorino:
Jimmy Pegorino is Ray's boss. He is a loud, obnoxious, paranoid, and selfish man. He mostly has Niko kill people he no longer wants alive, in a variety of ways.

Content review posted: 05/09/08