There was originally a restaurant named "Fanny Crabs" which would be based off of the real life restaurant, "Fatty Crabs". Sound files still exist for the workers. The name is also British slang for pubic lice on a woman's genitals.

Graphics for a scrapped game mode called "Zombie Revolution" can be found in the game's files.

There are sound effects for a handheld minigun in the game's files.

In earlier versions of GTA IV, one of the Most Wanted criminals, Maxwell Caughlin, is listed on the database as Maxwell Caddy.

The Wooden Baseball Bat was originally going to be included in The Lost and Damned, but was cut.

There is an unused pinball animation in the game's files, meaning that pinball was likely planned to be playable at one point.

In the Ballad of Gay Tony mission "Not So Fast", the Jewish mobster who attempts to shoot Luis in the cutscene has a Pump Shotgun, but after the cutscene, the shotgun lying on the ground is the Combat Shotgun.

In the Ballad of Gay Tony trailer titled "Meet Luis Lopez", Luis is seen wearing the brown and black Perseus suit, but with blue jeans. This implies that it may have been one of Luis' already available outfits.

Cash registers throughout the game have a button that reads "Ask CJ". This is visible through the use of a sniper rifle, zooming in on the keypad of the cash register. This is a reference to CJ from Grand Theft Auto: San Andreas.

The multiplayer mode "Bomb Da Base II" pays homage to the GTA III mission "Bomb Da Base Act II". In both, the player must collect explosives and place them on a ship.

There are signs that the Well Stacked Pizza Co. from Grand Theft Auto: Vice City and Grand Theft Auto: San Andreas was originally meant to reappear in the game:

• Outside the store "Pizza This", the employees are still seen sporting the logo and some with "Well Stacked Pizza Co." on the back of their shirts.
• Logos and names of Well Stacked Pizza can be found at a shuttered storefront at the Alderney Casino in Westdyke, Alderney.
• The chain is mentioned on the Pißwasser website as a business partner of the beer company.
• When blocking the route of certain taxis, the driver will sometimes shout lines such as "Hurry up, I need to get to Well Stacked!" and on occasion "My Pizza Stack's gettin cold, move it!"
• Pedestrian-to-pedestrian dialog will occasionally involve whether Pizza Stack or Burger Shot is better.

During one of the powerboat outings with Brucie Kibbutz, he will call the Statue of Happiness the "Statue of Freedom", while the subtitles still say "Statue of Happiness." This suggests that the statue might have had a different name during development, but the audio file did not get changed to reflect the statue's final name.

The achievement/trophy "Finish Him" is a reference to the Mortal Kombat series, in which the announcer says the same phrase at the end of the final match.

The achievements/trophies "Join The Midnight Club" and "Top The Midnight Club" are possible references to the Midnight Club series which is also by Rockstar Games.

An MP5 was originally going to be the SMG as seen in early pre-release screenshots. It had a 15 round magazine. An image of Niko holding it confirms this. Niko would presumably fire it with both hands on the pistol grip, like the Micro SMG. Its design was later replaced to resemble the S&W MP10.

The setting of the game was originally going to be Liberty State, rather than just Liberty City, and it would have included countryside surrounding Liberty City, mountains based on the Adirondacks and Catskills, and possibly The Caraways.

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 the original Grand Theft Auto, where if the player runs over a line of Hare Krishnas, they get a Gouranga bonus.

Internal files call the Beechwood City area of Broker "Grayfords", suggesting that Grayfords was Beechwood City's original name.

An unused map icon representing a boat can be found in the game's files. Its file name is radar_boattour, suggesting that a boat tour service was once available in the game.

The pool cue from the pool mini-game is categorized as a weapon, but cannot be acquired outside the context of the mini-game, and thus cannot be used as a weapon. It has all the necessary data, including a HUD icon.