The demo shows off several interesting gadgets and moves too. We see the Phantom Cigar in action, which Snake can smoke to pass the time. This will allow you to change the conditions for each mission. In the demo, it's a dank, rainy day to start with but, as Snake puffs on his stogie, time passes. Night comes and goes, and the next day is much more clement. It's understandable that you'd want to tackle some missions at night, but it's unclear if the weather or time of day will have much impact on the gameplay.
Another nifty gadget is the Active Decoy. In the demo, Snake uses it in two ways. The first, rather amusing use, sees him bump a guard off a cliff-edge with the decoy. It then inflates in the shape of a person, drawing the attention of another near-by enemy. Snake then zaps this distracted fool with a power-glove. Later in the demo, Snake deploys three decoys while he's being chased by a group of militia. While they shoot up the inflatables, causing them to wither in a comedy fashion, Snake flanks his opponents and shoots them dead.
Looking for more information on Metal Gear Solid 5: The Phantom Pain. Just click on to the following slides for everything we know about the game.