When voice actors auditioned for their roles, they were told they were auditioning for a fake game called "Frozen".

Ricky Gervais and Katt Williams both did full motion and voice capture for their brief appearances in their own comedy skits at the Split Sides Comedy Club and on the in-game television.

With an estimated budget of $100 million (US), it held the record for the most expensive video game produced at the time of its release.

The character Niko Bellic is based on Vladimir Mashkov's character from Behind Enemy Lines (2001). Mashkov was offered the role (voice), but turned it down because he didn't take it seriously at the time, as he explains in the talk-show interview Pozner: Vladimir Mashkov (2010).

The first Grand Theft Auto game to feature ragdoll physics, dynamic lighting, realistic water physics, realistic object physics, and realistic NPC/World interaction.

According to the LCPD online database, Little Jacob's full name is Jacob Hughes, Real Badman's given name is Teafore Maxwell-Davies, and Playboy X's given name is Trey Stewart. It also establishes Mrs. McReary's first name as Maureen.

The MP3 ringtones Niko can buy for his mobile phone are real songs from the Grand Theft Auto: Liberty City Stories (2005) (VG) soundtrack.

One can access the LCPD online database by going to the LCPD website on the in-game internet, scrolling to the bottom of the page, and clicking on 'Database'. The database is accessible from the very beginning of the game.

The first line of dialogue is "Daddy's back bitches". The line is repeated in Grand Theft Auto V (2013) by Michael De Santa, one of the protagonists.

Dan Houser, co-founder of Rockstar Games, confirmed at E3's 2006 convention that the game will feature Multi Conventional Tesseract technology otherwise known as MCT or "Octachoronics". This will allow for sharper and more innovative game play residing in assimilated artificial weather control systems. The in-game weather will never appear to be the same twice. Each rain drop will contain 20 herds.

The first of the series to feature sexual acts actually being performed by a prostitute on the protagonist. Other Grand Theft Auto games featured the player and the prostitute sitting in the front seats, motionless, as the player's vehicle rocked to and fro. GTA V took it a step forward by having the strippers being topless when giving lapdances to the three protagonists. The protagonists of GTA V can also take some of the strippers home for a booty call and the strippers number will end up being saved in the protagonist's phone.

In the game, Alderney is based on New Jersey. Being that it would involve a different state than Liberty City this area would not be patrolled by the LCPD. However, while the appearance of the police cars remains the same when you attract a wanted level in Alderney, the police uniforms do in fact change and differ from the other areas in the game and resemble the uniforms of the New Jersey State Police.

There are many rumors that the guy on the payphone for all the Assassin missions, is "The Truth" from Grand Theft Auto: San Andreas (2004), though this is not confirmed.

In some of the trailers and official artwork, Niko can be seen wearing gloves, however they aren't available in the game.

The storyline intersects with the events of both Grand Theft Auto IV: The Lost and Damned (2009) & Grand Theft Auto IV: The Ballad of Gay Tony (2009).

Information on the protagonists of the following three Grand Theft Auto games can be found in the LCPD online database: Johnny Klebitz, of Grand Theft Auto IV: The Lost and Damned (2009); Huang Lee, of the Nintendo DS game Grand Theft Auto: Chinatown Wars (2009); and Luis Fernando Lopez, of Grand Theft Auto IV: The Ballad of Gay Tony (2009). Both Klebitz and Lopez make cameo appearances in Grand Theft Auto IV (2008).

If the player goes to a certain level of the Statue of Happiness, there will be a non-solid door with a plaque next to it reading "No Hidden Content this way". If the player goes through the door, there is a ladder leading up to a gigantic beating heart with chains attached to it. It can be shot and blood will shoot out of it.

Chinese signboards are seen throughout the islands. Many of them are Homophones associated with slangs and dirty jokes in Hong Kong culture. For examples, "Bill Sze Accounting" can be read as "Poop-your-pants Accounting" in Cantonese. While "167" in Cantonese is known as "A piece of dick," a dirty way to say "dumb." "Mr. Mo Driving" can be translated ironically as "Manless-driving" or "Autopilot." There are also sarcastic jokes about the names, such as "Loan-shark-king Financial Loans," "Alopecia Hair Salon" and "Super Real Jewewllery," et cetera.

If viewed close enough, the player can see that the face of the Statue of Happiness actually resembles that of former US Senator Hillary Clinton and that the statue is holding a coffee cup in her right hand as opposed to a torch. This is a reference to Hillary Clinton having an issue with the "hot coffee" mini-game/feature in Grand Theft Auto: San Andreas (2004) which eventually was removed from the game after it's initial release.

Similar to the 'RIP Competition' memorial in Grand Theft Auto: San Andreas (2004), there is a memorial stone in a small graveyard in the borough of Broker that reads: 'For those of you about to build...we salute you - War of the Deadline - 1829-1829'.

The boat that Niko Bellic arrives on is named 'The Platypus'. The platypus is an animal that is native to Australia. Numerous references have been made about Australia in previous Grand Theft Auto games including references to the fictional Australian-American war.

Wu "Kenny" Lee can also be found in the LCPD online database even though he was not introduced until Grand Theft Auto: Chinatown Wars (2009) for the Nintendo DS.

A teaser site for WKTT, one of the in-game radio stations, invited people to call a telephone number to talk about how they felt about the state of America in the style of a talk radio phone-in. The best rants were included in the final version of the game.

At the beginning cutscene of the game, there is a poster of Grand Theft Auto: Vice City (2002)

The Xbox 360 version of Grand Theft Auto IV became backwards compatible for Xbox One on February 9th, 2017.

Ten years after the game's release, a patch came out on April 26th, 2018 that removed several songs from the radio stations due to licensing issues. A new playlist of tracks was added to Vladivostok FM after all except one of the tracks was removed from the station. The following tracks were removed: Liberty Rock Radio: "1979" by Smashing Pumpkins "Edge of Seventeen" by Stevie Nicks "Evil Woman" by Electric Light Orchestra "Fascination" by David Bowie "Heaven and Hell" by Black Sabbath Liberty City Hardcore: "Enforcer" by Leeway "It's the Limit" by Cro-Mags K109 The Studio: "Can't Live Without Your Love" by Tamiko Jones Vladivstok FM: Every song except "Liberty City: The Invasion" by Seryoga. Every other song was replaced by the following new tracks: "YA Nenavizhu Karaoke" by Aleksey Bolshoy "Mon Ami" by Seryoga (feat. Maks Loren) "Dobav' Skorost" by Seryoga "Chiki" by Seryoga "Goryacheye Leto" by Delice "Noch'Ju" by Zhenya Fokin "Gulyaj, Slavyane!!" by Kievelektro (feat. Alyona Vinnitskaya) "Begu (Rancho Song)" by Riffmaster "Riffmaster Tony" by Riffmaster "Underground" by Ayvengo "Reprezenty" by Ayvengo The Journey: "A Rainbow in Curved Air" by Terry Riley "Communique: 'Approach Spiral'" by Michael Shrieve Radio Broker: "Homicide" by The Prairie Cartel "The Teacher" by Ralph Myerz & The Jack Herren Band IF99: "Home Is Where the Hatred Is" by Gil Scott-Heron San Juan Sounds: "Ven Bailalo" by Angel y Khriz The Vibe: "C.O.D. (I'll Deliver)" by Mtume The Beat 102.7: "Crackhouse" by Fat Joe (feat. Lil' Wayne) "Stylin'" by Papoose The Classics: "All for One" by Brand Nubian "Droppin' Science" by Marley Marl (feat. Craig G)

The game runs on the RAGE game engine, the same engine that powers Rockstar Games Presents Table Tennis (2006). It also uses Euphoria animation software by NaturalMotion, allowing realistic body physics such as catching ledges before falling over, and stumbling when intoxicated.

In New York City, the location on which the game is based, there is no penal law charge for "grand theft auto". The appropriate charge there would be "grand larceny auto".

The developers included an anti-piracy measure that once an illegal copy of the game is detected, the camera starts wobbling after a few minutes. In addition, the brakes on the vehicles won't work.

Similar to the radio advert in Grand Theft Auto III (2001) for 'PetsOvernight.com', there is an advert for 'BabiesOvernight.com', some of the wording in this advert strongly resembles the Pets Overnight advert, including the quote 'Delivered, in a box, directly to your door'.

The stand up Katt Williams does at the split sides comedy club is from his stand up movie American Hustle the movie

The character of Brian Meech, one of the random characters that Niko can meet on the street, tells Niko on their third meeting that he resorted to performing oral sex on people to support his heroin habit. This is close to the same story as Rick Shapiro, who features on the PLR radio station within the game.

The Perestroika cabaret club in Broker is owned by Russian mafia member Mikhail Faustin. Perestroika was a name given to the political and economic reforms of the Soviet Union by then-General Secretary Mikhail Gorbachev. Not only is it strange that they both share the same name, it should also be noted that the literal meaning of Perestroika is "restructuring", possibly referring to either the rebuilding of the old ways in the USSR in Hove Beach, or referring to the restructuring of one's life in America. Also, there is a restaurant in Broker called "Little Gorbachef's", an aobvious reference to Mikhail Gorbachev.

Removed locations had the names "Anger Bay" (based on Pelham Bay), Norfolk (NoHo), Jefferson Heights (Hamilton Heights), Acter Bay (South Kearny), Richmond (Richmond Hill), Frogtown (Turtle Bay) and a representation of Washington Heights.

When shooting civilians/enemies/police, often times they will be incapacitated rather than outright killed (unless shot in the head or harmed further). They may writhe on the ground, call out to the protagonist character (usually pleading for their life), and even attempt to stand up only to limp away wounded. Enemies marked with a mission objective marker (whom the player must eliminate) are no longer considered a threat when in this incapacitated state, most likely because they always drop their weapon.

All of the car license plates read 'LIBERTY CITY', a possible reference to Grand Theft Auto III (2001)'s 'LC R29' license plates.

When visiting the airport, jumbo jets can be seen taxiing the runways. They will never actually take off, and taxi around the runways in circles indefinitely. Airplanes can also be seen flying over the city which follow a continuous circular path around the entire city. When the airborne planes approach the airport, they will dip down and subsequently fly up to give the illusion of planes landing/taking off, though they never actually touch the ground.

Where Niko Bellic is really from is highly controversial, as it is never directly mentioned in the game, except that he is from the Balkans and is Slavic. Earlier in the game, Roman mentions the word "Serbian", which is a Slavic language that Niko speaks. Serbia itself is in the Balkan region. Niko himself is a veteran of the Yugoslav Wars that tore apart much of the former Yugoslavia throughout the 1990's. Given that Serbia was never directly involved in much of the fighting in neighboring Croatia and Bosnia, although it initially provided strong support for Serb communities in both nations, Niko was most likely from either Bosnia or Croatia, but most possibly the former. The civil wars in Bosnia and Croatia became notorious for the numerous war crimes that were committed by all sides, especially the atrocities committed in Bosnia. Niko Bellic himself has hinted that he took part in war crimes. It should be noted that even though all sides committed atrocities in the Yugoslav Wars, the crimes committed by Serbs were seen as the most notorious.

The main characters in the series will meet each other at least once.