Actor Allusion: Kiefer Sutherland was cast as the new voice of Snake in part as a reference to his role in as Jack Bauer in 24. After seeing Snake in the prison camp Chico starts to panic and begins drawing attention to them. It doesn't take long for Snake to apply a sleeper hold on him while saying "Don't fight it."
Colbert Bump: Garbage's song "Not Your Kind of People" had a sales rise on iTunes after being featured in a Metal Gear Solid V trailer.
Donna Burke, who sang "Heavens Divide" and "Sins Of The Father", voices the iDroid.
I Knew It: Many fans and sources speculated that The Phantom Pain was actually a Metal Gear game well before it was announced as such, thanks to the clues left in the original trailer.
A number of people had figured out that the creepy child with a gas mask was actually a young Psycho Mantis, or that he was at least involved with the mysterious organization of "Those Who Don't Exist". This was eventually confirmed by Game Informer about a month before the release of Ground Zeroes.
Lying Creator: Kojima kept insisting that "Project Ogre" was not, in fact, a production title for Metal Gear Solid 5 prior to the reveal of The Phantom Pain. Turns out, it was. However, this is actually an instance of him being misquoted, because his original statement was in reference of Ground Zeroes at the time.
Never Live It Down: Kojima has stated that the issues in this game are so sensitive that he would no longer be able to continue working in gaming if he screws it up. Consideringwhat'sinGround Zeroes, the trailers of The Phantom Pain and the implications following it, you can kind of see where he's coming from. Thankfully, as far as reception towards Ground Zeroes has shown, it seems that the way he's handled the heavy subjects has been met with praise instead of controversy, for the most part.
Speaking of Ground Zeroes, however, the game's extremely short length and meager amount of extra content despite a 30 dollar price tag has led to its own breed of controversy.
Talking to Himself: Kiefer Sutherland (apparently) voices both Snake and Ishmael, and the two share a scene together at the start of The Phantom Pain. It has been confirmed that he voices the medic that appears in Ground Zeroes, but his voice was altered digitally.
The Other Darrin: David Hayter was replaced by Kiefer Sutherland as the voice and motion capture actor of Big Boss to help "recreate the Metal Gear series." Meanwhile, Ocelot is being voiced by Troy Baker instead of Patric Zimmerman.
Trolling Creator: Not necessarily Hideo Kojima, surprisingly, but rather David Hayter. He's left some bitter comments about the game that seem strangely out of character for him, considering his usual personality. He's also left a couple of hints that he's involved with the game on his Twitter (such as feeling a sudden case of laryngitis coming on, or the infamous "New Coke" message), but nothing's certain.
After months of focusing on other projects, it seems that Hayter is at this again. He changed his Twitter image to a photo of Sutherland shortly after Ground Zeroes hit the shelves, and then retweeted an image of Sutherland receiving credit for writing the script to Watchmen. Is this just a harmless joke, a Creator Breakdown, or a hint at things to come? Who knows?
Several hallmarks of the other games were removed from the game in order to make the game more realistic and serious, such as Ration-based healing. Originally, Kojima thought about removing the trademark exclamation point, in favor of realistic expression from the enemy (as had been planned for MGS4 as well). Thankfully, it seems that the grandfather clause prevailed.
Skull Face's original name was supposed to be Scarface. He was also meant to appear on the box art for Ground Zeroes, but he was removed because Kojima thought that would be too creepy.
More accurately described as "What Could Be": Kojima was asked if he would be interested in developing a Silent Hill game. He stated that he might not do a horror game justice. After seeing The Phantom Pain trailer, fans think he might be able to pull one off. He didn't say "no" or that he wouldn't at least contribute something. Becomes Hilarious in Hindsight when Silent Hills was revealed with Kojima being one of the directors.
Quiet originally looked a lot like Paz in a bikini.