When Jimmy is kidnapped, he calls Michael and tells him he's in a charcoal-colored Landstalker. But when Michael catches up to the car, it's colored green. (Note: this has been corrected in the Enhanced version of the game.)
Along the highway in rural areas, traffic cops (Called the San Andreas Highway Patrol in-game) can be found standing and watching the highway with police motorbikes next to them. However if driven past with a wanted level or provoked, they'll usually and strangely commandeer a civilian car rather than use their bike (unless they're sitting on it when you go past).
In the mission "The Wrap Up", Michael De Santa, Steve Haines, Dave Norton & Andreas Sanchez are engaged in a Mexican Standoff with Merryweather and the FIB. Steve's gun used in the standoff was an automatic pistol. However, when Steve shoots Sanchez in the head, the gun is set to a single shot.
At the beginning of "The Big Score", the characters exit the Vanilla Unicorn through the backdoor, yet in the very next shot, they're seen coming out the front door.
The door to Floyd's apartment does not have a doorknob.
When you are taking your flight lessons the instructor asks you to perform a barrel roll. In fact the maneuver performed is an aileron roll. A barrel roll is a different kind of maneuver.
The moon's position in the sky relative to the sun isn't always correct. A full moon always rises as the sun sets while a thin crescent moon always rises just before or after the sun.
Runway numbers in the game are not correct. Airport runways are numbered according to what heading an aircraft using the runway will be on. For example runway 18 will be used by airplanes headed south, heading 180. The other end of the runway will be numbered 36.
At Michael's "funeral", there's no pile of dirt anywhere near his open grave.
Guards at the prison in Blaine county and soldiers at the U.S Air force base can be seen using AK-47's. The air-force would NEVER issue these weapons to soldiers and it's very unlikely that a US prison would issue these weapons to guards.
The morgue workers examining Michael in "Dead Man Walking" should have realized immediately that he was still alive, as he would clearly have a pulse. However, there have been real-life cases when people thought to have died had woken up later in the morgue despite authorities handling their bodies.
The LSPD officers hats' say "Sheriff" on them, when the sheriff's department is separate from the police department.
One of the signs at a building in Mirror Park cites the Los Angeles Municipal Code, but Los Angeles does not exist in the game's universe.
During "Father/Son", the glass of whiskey Michael drinks from never loses any liquid.
The U.S. Army soldiers refer to themselves as Marines sometimes.
Lazlow's co-host on "Chattersphere" Michelle Makes is said to be a millennial in her early-twenties but the voice actor who plays her is clearly much older.
The song "I Get Lifted" by George McCrae incorrectly includes a writer credit for K. Murray, & E. Sermon. New York rapper Keith Murray sampled the George McCrae original as it plays within the game for his own track called "Get Lifted".
The character of Impotent Rage is credited twice, with two actors named as voicing the character. This is because 'Frank Simms (II)' voices the cartoon character, and Graham Rowat voices an actor dressed as Impotent Rage outside the Hardcore Comic Store in West Vinewood.
Because of the way the game's spawning system works, if you hang around or near a railroad track, a train will come past every few minutes, but you can drive along the tracks for miles without running into a train.
The GTA games are set in a universe where places have alternative names to their real world counterparts (New York City is Liberty City, Los Santos is Los Angeles, Hollywood is Vinewood etc). Most of the songs on the in-game radio stations are real life songs not written specifically for the game. Some of these songs, such as Hollywood Nights by Bob Seger and Los Angeles by X, reference real life places in their lyrics. If these songs existed in the GTA universe, they would be called Vinewood Nights and Los Santos respectively.
In the darts mini-game the human player always gets to throw first. In real darts competitors take turns to go first, just the same as the alternating serve in tennis.
The U.S. military uses jeeps in the game, when they were replaced with Humvees long ago.
The North Yankton State Patrol (NYSP) are seen using sedans and SUVs that are based off vehicles from the 1980s despite them appearing in the section of the game that takes place in
2004. This is incorrect as police departments across the U.S. in 2004 were using the more modern post-1998 Ford Crown Victoria (and many of them still are).
U.S. cars are mandated to have a CHMSL third brake light since the mid-1990s but a lot of the newer cars in the game don't have them.
A tap dancing red neck can sometimes be seen west of Grapeseed. Though he is dancing on dirt it sounds as if he is dancing on a hard surface like wood.
After "The Long Stretch" Franklin can go into his aunt's house, but their conversation implies that the door is locked and that his aunt's friends are with her when she is actually just sitting on the couch staring at the TV which isn't on.
The game is set in the U.S. but some of the exit signs inside buildings are UK-style ones, green with a running white stick figure. U.S. exit signs are usually beige rectangles with "EXIT" in red or green letters.
Inside the stores, the potato chip bags have "Flavor" spelled the British way "Flavour". In the U.S. it is spelled "Flavor" without a "u".
If you play "Bury the Hatchet" as Trevor, you are meant to fly to North Yankton, though the way-point is located offshore to the west, when in actuality, North Yankton is EAST of San Andreas.
At the beginning of "Scouting the Port", Trevor gives stolen dock worker uniforms to Wade and Floyd. Since Floyd already worked at the dock and had a uniform, there was no need to give him one.
During "Monkey Business", Steve Haines shoots himself in the leg. During "The Wrap Up" (which takes place only a few days later), he is already walking normally, with no injury whatsoever.
When viewing Taliana's heist profile, Michael will say that she's "suppose to be good". If Franklin or Trevor came to her rescue instead of Michael, then he shouldn't know anything about her.
Even though it was established that Lester can only walk with the aid of a cane, during the mission "Cleaning Out the Bureau" when he and Michael return to the factory, Lester is able to walk up stairs perfectly without the use of his cane.
In the mission "Friend Request" Mike leaves the back pack behind in the office after rigging the prototype to explode. This would have been really stupid considering the police would collect it and analyze it for evidence.
When getting the gold from the Union Depository the bank manager mixes Empirical and Metric units. (ounces and Kilograms). Because this games takes place in what would be the United States it is more likely the 4 tons mentioned would be short tons. 1 short ton is equal to 2000 pounds or 907 Kilograms.
During the opening cut-scene of "Fame or Shame," Amanda yells at Michael about their living situation, then she concludes her rant with "thank you, Michael whatever the fuck our fake last name is." Since they have been living under that name for nine years, it's unlikely Amanda would suddenly forget it.