- In Three Leaf Clover with Patrick McReary, if you position the camera properly you can look inside his head - inside there is a box with a picture of a brain on it.
- Within the Statue of Happiness is a giant beating heart, supposedly the "Heart of Liberty City." In GTA IV, access into the area is only achievable via an entrance marked by a "No Hidden Content This Way" sign at the upper level of the the statue's pedestal, which can only be reached by helicopter. Once inside the pedestal, the player must scale a ladder up to the midsection of the statue, where the heart is located. In The Ballad of Gay Tony if you drink too much you will respawn at random locations, one of which may be the Heart of Liberty City.
- If you look at the lake in Middle Park by map or helicopter, you'll notice it is in the shape of an alien.
- In northern Alderney, where you make the jump in the mission Out of Commission, there is a person doing tai-chi on top of a high rock which is impossible to get to without a helicopter or trainer.
- At the Firefly Projects, there is a park with a swing set. If you drive backwards (or forwards with some vehicles; Voodoo) onto it, the swing set will catapult the vehicle you're in high in the air. This is likely a bug in the game's physics simulation. See Swing Glitch article for more details.
- While driving the Mr. Tasty, you can trigger songs to play by clicking the horn. One of these songs is the song from the opening credits of GTA IV. While this song is playing, call ZiT and they will text you back with "ZiT! Spotted GTA IV Theme". This is a cheat that gives the player health, armor and ammo, but also disables some achievements.
- When you acquire your Second Safehouse in Bohan, when you exit the front door, over the road, you can see a random NPC talking about the end of the world and the apocalypse. Enter the building next to him and after you get up a few stairs, in a passage you can see blood and a pistol on a floor.
- During one of Brucie's mission "Easy as Can Be", If you look on the lower part of his stomach, you will see a tattoo that says "Mommy" on his stomach. You will be able to see that when he has his shirt off.
- At all TW@ internet cafes, behind the cashier's desk, and also inside various vehicle dealerships the screen of the Kakagawa Power Ultra 3000 Pro photocopier reads: ERROR Unleash ninja guru lol. This can only be seen through the scope of a Sniper Rifle.
- If you take a helicopter ride from Brucie Kibbutz, or you go for a helitour, there's an unsettling warning message about the helicopter inside the cockpit that you can see if you look in first person mode that says "This helicopter might crash but we really don't care if it does, refer to flight manual for help."
- In The Lost and the Damned, the dash of the Rhapsody has a sticker of Wayne and Garth from the movie Wayne's World.
- While playing multiplayer, all TV's in safehouses show the game's pause menu without the map.
- In the Northern Alderney car wash and gas station, parked cars may have their hazard lights on. If you drive the car, they will still be on.
- Behind an old, rundown mansion in Westdyke, Alderney at the end of the dirt roads, there is the hidden, extremely rare Sultan RS parked in some bushes. This is practically the only way to find the car ingame. The only other way to obtain it is if the game has it stored in the temporary memory, and automatically spawns it parked and driving around the streets.
- On the west side of Happiness Island there is a random spawn that can be a car. This is unusual as there is no way a vehicle can be brought on to the island unless unloaded by a ship.
References to previous games
The graffiti found on certain run down apartment corridors. Scribbled text that read "Claude
" and "Victor/Vic
" are visible.
- On the staircases in most apartment blocks in the game, some graffiti pay homage to past protagonists set in GTA III canon (Claude, Tommy Vercetti, Carl Johnson, Toni Cipriani, and Victor Vance) in the form of scribblings of their names on the walls. Writings such as "remember tommy, u r still my hero" or "we always remember u bro" may be a possible reference to the gamer fandom towards the characters.
- Numerous companies from the GTA III era (for example Sprunk, Burger Shot and Maibatsu) return in GTA IV.
- One of the TV shows is a program called The Venturas Poker Challenge. It features a casino in Las Venturas from GTA San Andreas. When shown, the commercial doesn't have GTA IV graphics and art, it features GTA San Andreas graphics, the most obvious being the Taxi.
- In Star Junction there is sign for Love Fist. Love Fist was featured in GTA Vice City, and was also on a sign in GTA San Andreas and GTA Liberty City Stories.
- In the apartment in Bohan, next to the coffee table and in front of the bed, are a few CDs laying on the floor. Zoom in with a sniper to see that one of the CDs is by OG Loc from GTA San Andreas. There is also one by Madd Dogg.
- There is a laundromat in Alderney called Mr. Wong's Laundromat; this is presumably a nod to that particular location.
- When Playboy X is killed, it is possible to go to his apartment and open the wardrobe to get a change of clothes that look like the clothing of Claude, the protagonist of Grand Theft Auto III.
- On the front of some Liberty Tree newspapers is Donald Love, who disappeared in GTA III.
- The Securicars are owned by the Gruppe Sechs security firm (also seen in GTA III and Vice City), although in GTA IV the name is rendered as "Gruppe 6". "Sechs" is the German word for Six and "Gruppe" means group.
- In the bars are postcards featuring Vice City. Vice City is also advertised in airfare billboards near the airport.
- The "Pager" ringtone on Niko's cell phone is the pager sound from GTA III.
- Niko can receive an email from Chiliad8888, which calls the recipient "Pilgrim", makes many spiritually- and philosophically-charged (and anti-government) comments, ends with "Feel the Truth, Live the Freedom", and links to whattheydonotwantyoutoknow.com. On this website there is a discussion topic titled, "Jump to a new level of Spirituality" posted by "Trooth". This discussion thread includes more philosophical thoughts, mentions peyote, and provides a map of the Unique Stunt Jumps in Liberty City. "Chiliad" was also the name of a location in San Andreas (the highest mountain, in the southwestern wilderness). These clues suggest that the author of the email and discussion topic is The Truth, a character from GTA San Andreas.
- On Happiness Island, in front of the entrance to the statue, it is possible to find a street-artist's easel/display stand with several pictures. These pictures are all concept works of many previous GTA characters. The easel can also be seen in south-central Algonquin, very close to where Hossan's random encounter takes place and in front of the The Libertonian.
- A while after the mission Diamonds Are a Girl's Best Friend, the news reports that a homeless man, Jerry Kapowitz, found the diamonds used in the exchange and planned to use the money to open a gun store in Vice City.
- If you look closely at the chart behind Gerry on the prison, you can see the penis-shape drawing the students at GTA 3 had drew.
- On the road that takes you on the East Borough Bridge from Dukes to Charge Island, the first building on the left has graffiti with paintings of past GTA character such as Misty, 8-ball in his convict outfit, the women in a bathing suit on the front cover of Vice City game box,and more.
- A Fruntalot billboard in Algonquin shows a man who is said to be Carl Johnson, the protagonist of GTA San Andreas.
- During a multiplayer race in GTA IV if the player equips a certain Female face (possibly 2) then hits a car in traffic or another player's car while pressing the talk button (L1 PS3), the character will sometimes exclaim,"This isn't San Andreas you hippie, DRIVE!" in reference to the wreckless AI driving found in the streets and nearly all intersections of San Andreas, such as the area where accidents happen the most, the Las Venturas sign.
- In multiplayer, if one player kills another with a vehicle, the HUD may say that they "gouranga'd" the other player. This is a reference to Grand Theft Auto 1, where if the player runs over a line of Hare Krishnas, they get a Gouranga bonus.
- Lazlow is referenced several times as resuming his career, and reference is made to the radio station he worked for in an earlier GTA III-era game.
- On the west side of Firefly Island, along the beach, the player may encounter a woman shooting photographs. (If Niko stands near her, she'll turn and take a photo of him, too.) This may be a reference to a unique photo-taking NPC seen in San Andreas' Flint County not far from a road bridge into western Los Santos.
References to other games
- In the amusement park in Broker there are blue/purple Hippo Statues, just like the ones from Manhunt.
- Numerous references are made to Carcer City, the setting of Manhunt.
- On the website Yourmexicandoctor.com, two drugs first seen in Manhunt 2 (Hingmyralgan and H4PP1) are shown to be for sale.
- On the TV channel Weazel, there is an animated TV show called Republican Space Rangers, which spoofs the Halo series, as it features space marines wearing a green armor that resembles the MJOLNIR armor as seen in Halo. In one scene, the Rangers fly their spaceship through a ring that resembles a HALO ring.
- The achievement/trophy "Assassin's Greed" is a reference to the Assassin's Creed video game series. Also, in Assassin's Creed: Brotherhood there is an achievement/trophy called Grand Theft Dressage, to obtain this Ezio must steal five horses in a row from guards without touching the ground.
- The achievements/trophies "Join The Midnight Club" and "Top The Midnight Club" may be a reference to Rockstar's Midnight Club video game series.
- The achievement/trophy "Finish Him" may be a reference to Midway's Game (present day Warner Bros) Mortal Kombat.
- For GTA IV's renditions of New York City landmarks, see Liberty City in GTA IV/New York Landmarks.
- The game references to the economic recession faced by the United States on a few occasions.
- Rockstar Games has a habit of putting its logo in its games; the bowling pins at the bowling alley have the Rockstar logo on them,
- The generic Angels of Death gangster dubbed "Fat Biker", has the Rockstar logo emblazoned on his belt buckle.
- In Cluckin' Bell restaurants, near the back of the store, there's an action figure of a man in a martial arts position wearing a chicken hat; printed on the glass is "Cluck Norris", a reference to film/television star and martial artist Chuck Norris.
- The mission Weekend at Florian's is a reference to the comedy movie Weekend at Bernie's (Florian insists that his new name is Bernie).
- The mission called I Need Your Clothes, Your Boots and Your Motorcycle is a reference to Terminator 2, in which Arnold Schwarzenegger says this famous line.
- Avenues running north-south (vertically) in Algonquin are named alphabetically after American cities. "A" is at the eastern side of Algonquin; "G" at the western. The names, in order, are Albany, Bismarck, Columbus, Denver, Exeter, Frankfort, Galveston. Denver and Exeter run concurrently ("Denver-Exeter Ave.") south of Middle Park into Star Junction.
- Streets running east-to-west (horizontally) in Algonquin are named alphabetically after different types of minerals. "A" is at the southern end of Algonquin; "X" at the northern end. The names in order are Amethyst, Barium, Calcium, Diamond, Emerald, Feldspar, Garnet, Hematite, Iron, Jade, Kunzite, Lorimar, Manganese, Nickel, Obsidian, Pyrite, Quartz, Ruby, Silicon, Topaz, Uranium, Vauxite, Wardite, Xenotime.
- Many street names in Bohan are named after prisons -- Leavenworth Ave, Alcatraz Ave, Sing Sing Ave, Guantanamo Ave, Attica Ave, San Quentin Ave, Folsom Way (best known from "Folsom Prison Blues" by Johnny Cash), Rykers Ave (named after the Rikers Island prison on the East River of New York City), and Joliet Street (Joliet, Illinois).
- In South Alderney, the street names reflect (mostly antiquated) military terms -- Musketeer, Grenadier, Chariot, Phalanx etc.
- In Broker, roads running North-South are named after Native American tribes -- Iroquois, Oneida, Mohawk, Onondaga etc.
- In Broker there are the street names "Cassidy" and "Sundance", a reference to the outlaws, Butch Cassidy and the Sundance Kid.
- The Beatles: Broker contains the streets "Ringo St" and "Starr St", both references to the Beatles member Ringo Starr. In Dukes there's a Harrison St., probably a reference to George Harrison, and the northwest section of Liberty City contains the Long John Ave, name that John Lennon used at the beginning of his career. Paul McCartney references not found yet.
- Rockstar uses cartoon characters names as street names such as, "Bart (Simpson), (Hubert) Farnsworth" and the direct link to South Park, "South Parkway".
- In Alderney, some streets are named after cult leaders: Hubbard St., Applewhite St., Koresh Square
- Some streets are named after tools -- Jackhammer, Plumbbob, Tinderbox.
- Some streets are named after animals -- Caterpillar, Worm, Butterfly.
- Some streets are named after foods -- Onion, Asparagus, Chive.
- Some streets are named after colonial Settlements -- Yorktown, Delaware.
- Some streets are named after famous surnames -- Harrison, Hancock, Livingston.
- Some streets are named after nuclear tests -- Plumbbob, Emery, and Niblick.
- Some streets are named after inventors -- Edison, Schneider, Moog, Drebbel, Farnsworth, Cockerell.
- The street in Northwood named Astoria's full name is Astoria Place. This could possibly be a take on Astor Place in the Lower East Side.
- At the beginning of Clean Getaway, Vlad is nearly hit by a taxi and shouts "Hey! I'm walking here!" in reference to the movie Midnight Cowboy.
- On the stairway leading to the sea at Meadow Hills there is a 'Banksy-esque' style graffiti piece.
- There is a Liberty Tree article that talks about urban myths in Liberty City. This could be referring to the myths that were created around San Andreas.
- An online article on Liberty Tree's website, an Air Sol flight has 212 passengers on board, 212 a reference to the area code in New York City.
- In Willis, there is a shop called Al's Furniture. This is a reference to Italian-American gangster Al Capone, who was officially the owner of a furniture shop.
- The fact that a secretive government body operates out of a paper factory may be a reference to the TV show Heroes. A secretive organization in that show also uses a paper factory as a cover and much of the action takes place in New York.
- The viral video, 2 Girls 1 Cup, is indirectly referenced to numerous times on the radio.
- In the mission Final Interview, if you shoot the guard standing at the top of the last flight of stairs when escaping from Goldberg, Ligner & Shyster, he will do a Wilhelm Scream as he falls down.
- There are a lot of people complaining that they have to smoke outside. This is a reference to New York City, where you can't smoke inside either.
- The achievement/trophy "Auf Wiedersehen Petrovic" is a reference to the British TV series Auf Wiedersehen, Pet.
A "Hot Coffee Shop" sign, a clear reference to the Hot Coffee
- As with previous games, the number 69 is used on various occasions in Liberty City, one such instance being on the Fire Trucks. 69 is a reference to the sexual position of the same name.
- The outside sign for the Memory Lanes bowling alley depicts a bowling pin with two bowling balls on either side of it. Inside, however, the sign is only a neon outline, and resembles a crude drawing of male sex organs.
- In many spots around Liberty City, there is rubble on the ground; in some of this rubble, you can see a purple dildo sticking out. This is the same dildo used as a weapon in GTA San Andreas.
- There are signs scattered throughout Liberty City that say "Hot Coffee Shop", clearly a reference to the Hot Coffee sexual content and controversy from GTA San Andreas. (Ironically, GTA IV and the DLCs contain more overt sexual content (i.e. hooker service animations, The Ballad of Gay Tony's booty calls) than GTA:SA's hot coffee.) [Verification Needed]
- Looking at the golf courses carefully from a height reveals that they are penis-shaped.
- A brand of beer in the game is called "Dusche Gold". "Dusche" is German for "shower", so it translates into "shower gold", a reference to "golden shower", the act of urinating on someone.
- Another beer brand is named "Pißwasser", "wasser" being German for "water" and "ß" is a German letter for "ss". An advertisement for Pißwasser shows a woman with the bottle in her mouth as if in an act of fellatio.
- The logo for AutoEroticar is a car resembling a penis.
- In East Island City, there is a building called the National Union of Contemporary Arts, within which is a statue of what looks like a stick figure man with an erection.
- In Middle Park there is a monument that resembles male genitalia. According to a plaque at its base, it is called "Le Knobeliske" and was presented to Liberty City by C. Shutchomouf in 2007.
- At The Airport a yellow sign on the runway says: "Caution Watch Your Blast"