During development Ilyena Faustin wore different clothes, which can be seen in the second trailer for the game.

The second trailer for the game shows that Real Badman didn't originally wear a hat, unlike in the released version.

Originally in The Lost and Damned mission, "Politics", Johnny was supposed to get a uniform to pass by security. This also means that Johnny may have been able to have changed outfits in development.

The Fight Club was originally going to be introduced in The Lost and Damned, but it was cut until The Ballad of Gay Tony. There are still files referencing it in The Lost and Damned.

Female police officers were originally going to be implemented in the game before being cut. One can be seen in the first trailer for the game.

During development Michelle had a different face to the release version, as seen in the "Move Up, Ladies" trailer.

In the PC version of the game, the cook on the ship at the beginning of the game has a full beard; however, in the console versions of the game, he is clean shaven.

In the mission, "Wrong is Right", an email from a "Larry Ligner" sent from ligner@goldberglignerandshyster.com can be found on Oleg Minkov's computer. This would suggest that Larry was an early name for Patrick Ligner.

In The Ballad of Gay Tony, during the mission, "Boulevard Baby", a low quality map of Salem, Massachusetts can be seen on the desk in Vic's office.

During the mission, "Clean Getaway", while Niko and Vlad are walking to Vlad's car, Vlad is nearly hit by a Taxi and yells "I'm walking here" at the driver. This is a reference to a scene in the film "Midnight Cowboy", in which Dustin Hoffman is almost hit by a taxi and yells the same phrase. It may also be a reference to the film "Back to the Future Part II", in which Martin McFly Junior is almost hit by a car while crossing the street and yells the same phrase repeatedly.

The GPS usually makes an instrumental "bing bong" sound when approaching a turn. On rare occasions, the voice will actually say, "bing bong".

There are unused textures for Tony, Mori, and Brucie's names for when playing darts in The Ballad of Gay Tony. This implies that they could all be taken out for friend activities at some point in development.

A restaurant was planned to appear in the game called "Ping's". Audio associated with the restaurant still exists within the game's files.

There are multiple sound files for a golf kart in the original game, meaning they could have been planned to be implemented before the Ballad of Gay Tony.

The game was at one point going to have bus drivers. They were cut for unknown reasons, but they appear to be fully modelled.

Originally, Little Jacob did not wear glasses.

Mickey originally didn't wear glasses and wore a different outfit.

The pistol's chamber was originally black instead of grey.

According to an interview with Dan Houser by the Official Playstation Magazine UK, Staten Island was not included in the game because the development team decided that it wouldn't be a fun location to play in.

Originally, ice cream could be bought from street vendors. Sound files still exist in the game's data.