This is a dark and weird story with a Jacob's Ladder/Silent Hill feel to it. It's about a team of recon marines investigating strange phenomena in the wilderness of Argentina in 1977. The movie is about 7 and a half minutes long.
There is a lot of symbolism in the story. The main theme of the story is that when someone is socially outcast, an emotional "demon" starts gnawing at them from within. After a while, this "demon" may cause the person to snap and lash out at those around him. The tentacle demon that you see brief visions of represents this.
Also, this is part of a longer story that will be fleshed out more in later flashes. So it's a little vague for a reason.