The video shows Snake sneaking into an enemy base (complete with smarter, more adaptive enemies), and reveals that the world will be populated by various wildlife. Animals like wolves might attack you, so you'll always need to be on guard.
Finally, the Metal Gear Solid V: The Phantom Pain video shows off what appears to be the game's multiplayer mode. At around the 17-minute mark, we see Snake entering another player's base. We see that players can outfit their bases with all sorts of high-tech traps and gadgetry. The clip culminates with Snake being confronted by a character who appears identical to him.
During Gamescom, Kojima revealed that Metal Gear Solid V: The Phantom Pain and prologue Metal Gear Solid V: Ground Zeroes are coming to PC. Official release dates were not announced, but Ground Zeroes will come first.