There's currently a heated debate among the Metal Gear Solid community as to whether Big Boss can canonically smell or not, because the implications massively change one scene in The Phantom Pain.
When you begin Metal Gear Solid 5: The Phantom Pain, you're prompted to enter your birthday. This isn't an age verification check - it's actually to prompt the scene just below, in which Diamond Dogs celebrate Venom Snake's birthday by rolling out a big birthday cake for him, accompanied by a cigar handed to him by Revolver Ocelot to mark the occasion.
This scene has weirdly caused a lot of newfound speculation among the Metal Gear Solid community. At the one minute, 33 second mark, you can see Venom Snake smell the cigar, and if you keep your eye on Kaz Miller during that sequence, you can see the character's face change to an almost quizzical look. This is what the Twitter user below has only just realized, nine years after The Phantom Pain released.
Idk if I'm overanalyzing, but during the bday cutscene in MGSV Venom Snake sniffs the cigar, and then Kaz looks at him with a straight face because canonically Big Boss can't smell anything pic.twitter.com/pI3vguKhS1July 6, 2024
Miller's facial expression changing in this scene revolves around the fact that Big Boss, who Venom Snake is masquerading as, canonically can't smell anything. The Twitter user is positing that this is in fact a teaser that Venom Snake isn't who he's made out to be at all, which Metal Gear Solid 5 doesn't reveal until the closing moments of the entire saga.
Many are now hypothesizing that this is very deliberate from game director Hideo Kojima, meant to signal to anyone paying attention that their Snake is something of a false idol. That's what the Reddit post below believes - that all this is a tiny, deliberate seed in the grand overarching storyline of Metal Gear Solid 5: Ground Zeroes and The Phantom Pain.
Knowing Kojima this is intentional from r/metalgearsolid
This might not be so clear cut, however. Big Boss not being able to smell stems from a moment in Metal Gear Solid 3: Snake Eater, where Naked Snake tells The Boss that he can't smell anything whatsoever. It's just another zany moment in the very whacky series, but this line is not the subject of heated debate among Metal Gear Solid fans.
Some believe this is actually a wink at the player, as the player themselves can embody Naked Snake through sight and touch, but not smell. These fans believe this is something of a fourth-wall break from Kojima, acknowledging that the one thing the player can't actually do is smell through the screen, even though they can step into Naked Snake's shoes with his actions.
"When The Boss tells him to use all his senses and Snake just says 'I can't smell' with no other explanation, and The Boss just accepts it, I thought it was just a fourth wall joke. Snake can see, hear and feel, because the game has graphics, sound, and vibrating controllers. But we don't have smell TVs yet, so he can't smell," writes one very reasonable commenter on Reddit.
"Knowing Kojima, I believe it to be intentional. But honestly even within the game itself this was the worst kept secret of all time with the subtly of a brick smashing a glass window. There is no way anyone got to the end of MGSV and didn't just go 'There it is,'" writes one Twitter user, believing that the scene with Miller is actually an intentional clue from Kojima as to Venom's true identity.
Just about everyone has a different opinion on this, and I don't think Kojima himself is about to provide any clarity on the matter, unfortunately. It's just another little mystery in Metal Gear Solid 5 left unsolved, like what the hell Eli does after the Lord of the Flies incident, or where Diamond Dog's research into that big old tank ended up.