The following is a list of secrets, easter eggs, and hidden trivia references in Grand Theft Auto IV.
Easter Eggs
- Inside the Statue of Happiness is a giant beating heart. This is supposedly the "Heart of Liberty City."
- Whilst on a mission with Packie, if you position the camera porperly you can look inside his head - inside there is a box with a picture of a brain on it.
References to previous games
- Descending down the stairs of your first apartment in Hove Beach, you may spot some graffiti referring to past GTA protagonists Claude, Tommy, Carl (CJ), and Toni.
- There is a Sprunk manufacturing plant in Alderney. Sprunk was featured in GTA Vice City, GTA San Andreas, and Manhunt. It has returned to GTA IV with a brand new look.
- One of the TV shows is a program called Las Venturas Poker. It features a casino from GTA San Andreas.
- 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.
- 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 a laundromat in Alderney called Mr. Wong's Laundromat; this is the same one from GTA III.
- When you kill Playboy X, go to his apartment to get clothes that that look like the clothing of Claude, the protagonist of GTA III.
- On the front of the Liberty Tree is Donald Love, who disappeared in GTA III.
- The Securicars have the words Gruppe 6 on them, a reference to the Securicars in GTA III and GTA Vice City, which had the words Gruppe Sechs (group sex) on them.
- In the bars are postcards featuring Vice City.
- The "Pager" ringtone is music from Vice City.
References to other games
- One of Rockstar's rivals, THQ's Saint's Row, has been parodied on various billboards and signs throughout the city as a seafood restaurant called "Squid Row - Budget Seafood."
- In the amusement park in Broker there are blue/purple Hippo Statues, just like the ones from Manhunt.
Real-world references
- 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.
- 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," which is a parody of television star Chuck Norris, an expert in martial arts and the inventor of his own martial art and the roundhouse kick.
- 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: Judgment Day, in which Arnold Schwarzenegger says this famous line.
- 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 (Is named after a prison that sits in the East River between Queens and the mainland Bronx, adjacent to the runways of LaGuardia Airport called rikers island in New York), Joliet Street
- 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.
- Amethyst, Barium, Calcium, Diamond, Emerald, Feldspar, Garnet, Hematite, Iron, Jade, Kunzite, Lorimar, Manganese, Nickel, Obsidian, Pyrite, Quartz, Ruby, Silicon, Topaz, Uranium, Vauxite, Wardite, Xenotime
- On the Algonquin Bridge from Algonquin to Broker, on the right is a building with the name "CLOCKTOWER"; this is the reminiscent of the "WATCHTOWER" building of the Society of the Jehovah's Witnesses in Brooklyn.
Adult humor
- 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.
- 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
- 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 "Golden Shower."