Trivia: If an area has a missing texture that wasn't covered by the graphics team, there's a message on the walls that reads "I suck at making maps." This was something left by the level designers for the graphics artist to help them in placing textures on some walls. There is one elevator that if it glitches and doesn't spawn and you fall down the elevator shaft, you will find a few panels like this displaying this message.
Trivia: Hood Safari: When Franklin, Trevor and Lamar are approaching Grove Street, three men who bear a resemblance to CJ, Ryder and Sweet from Grand Theft Auto: San Andreas, can be seen driving away from the cul-de-sac in bikes. This is a reference to the mission Sweet and Kendl from GTA: San Andreas in which they have to ride bikes to evade a gang.
Trivia: A long running mystery of this game, there is one spot where an abandoned building is off in the distance. If you unlock the camera and head to that spot, you can find an odd figure of a man standing there. It is unknown who this is or why it's there, being an unfinished abandoned area of the game, or a detail, or just some odd bug. One theory is that it seems to resemble one of the game developers Shigenori Nishikawa.
Trivia: There is a building that, if you climb up it and get out of bounds, you will find an unfinished RPG weapon sitting up there that you can use. It's just suspended in mid air. This weapon was meant to be removed from the game as the developers decided it didn't fit in with the game's setting. This RPG did appear in previous CoD games but not this one, except an unfinished version of it on that one map. The gun is incomplete, missing some animations and sound effects but is still mostly functional.
Trivia: In the Chicago level, there is a piece of swiss cheese hidden inside the toilet seat in the bathroom.
Trivia: In one of the shacks, the devs hid an Easter egg referencing Back to the Future 3. In the shack, there is a tarp with the shape of the DeLorean underneath it. Also if you look in front of the DeLorean, on the table is the model train set similar to that of the train set used in the movie to demonstrate the time jump in Doc Brown's model.
Trivia: 'City of Ashes': in the hospital scene, there is a board on the wall with the names Dr J. Mengele, Dr W. Heisenberg and Dr G. Rasputin listed, referring to the infamous Nazi-German doctor/anthropologist, Joseph Mengele, German nuclear scientist, Werner Heisenberg, and Russian monk/witchdoctor, Grigorij Rasputin.
Trivia: When Elrond is welcoming Frodo into Rivendell, a LEGO character can be seen in the background wearing a black suit and tie. The character is none other than Agent Smith from The Matrix. Agent Smith from The Matrix and Elrond were both played by Hugo Weaving.
Trivia: In the bonus room, there is a door marked "Trailers" which lets you watch the trailer for LEGO Indiana Jones: The Original Adventures After viewing the trailer, you can buy Indiana Jones. The entire trailer must be viewed to unlock Indiana Jones.
Trivia: To unlock Han Solo, you have to find C-3PO, Luke Skywalker, Princess Leia, R2-D2 and Chewbacca. Once you do this, he'll be available to buy for 100,000 studs.
Trivia: The Apocalypse/Mayhem: During the cut scene where you see Abaddon and before you fight Straga, there is a moment when a Minion Demon tackles an Angel out of the sky next to a billboard on a building. If you look closely at that sign, there are various names on it. These names are people who are part of the Darksiders' development team. Names including John Tran, Howard Tang, Bri Thatcher, Nick Southam, Chris Doerr, Jeremy Robins, Pedro Seminario, and more.