Only Kojima could imbue so much into mere seconds of video.

The first glimpse is of Venom Snake being on his knees in a bloodstained hallway reminiscent of Gray Fox's killing spree in Shadow Moses. The hallway also reminds me of The Phantom Pain's hospital intro. Snake's posture here is reminiscent of the trailer from E3 2014.

The second glimpse shows a mirror image of Venom Snake. His face is drenched in blood, and his horn is longer and bigger than it's ever been. It's likely that Snake's horn grows longer over the course of the game (similar to how Geralt's beard grows in The Witcher 3, except Snake's horn will grow over a much longer period of time and will likely not be a cyclical process). This may indicate that this scene in particular takes place much later in the game. I wonder how this compares with how long his horn is shown during the MGSV preview event (after 12-16 hours of gameplay)? I think comparing these scenes will give a vague indication that TPP is truly a massive game.

I think it's well known by now that the horn and blood are references to demons; the blood on Snake's face in particular points to the Red Oni of Japanese folklore. Then you have the mirror. The teaser shows Snake smashing it into pieces.

Mirrors have been a large theme in MGSV ever since the very first Ground Zeroes trailer was shown back in 2012. FOX|XOF, dd|bb (Diamond Dogs|Big Boss), Snake|Quiet, Snake|Skull Face, Eli|David, Red Oni|Blue Oni, etc. Reflections are going to be a massive theme in this game. And a lot of elements in this game will be a reflection of Snake himself. In this case, what is the significance of Snake shattering his reflection? Does he despise the image of himself (or rather, the image that only he sees)? Does it have anything to do with the injuries he sustained in Ground Zeroes?

And thanks to some preview shenanigans, there have been rumors floating around; spoilers never meant to be seen. In this context, how does Snake reflect the player? And how will the player reflect on Snake?