Far Cry 4 will not only offer an increrdible single player experience as you try to survive in the wilds of Kryat but you can also play the game with friends, even if they don't have their own copy.
Players who pick up the game on PlayStation 4 version of the game will also receive 10 Keys to Kryat. You can give them to any of your friends on PSN and they'll be able to leap into co-op action with you, even if they don't have the game.
The play session will be limited to a maximum of two hours per key but 20 hours of free gameplay is a pretty generous offer. And if your friend hasn't bought the game by then you can't really consider them a friend!
Here's some trailerage.
Playing with the complicated mechanics of the Far Cry universe with another person sounds like its going to be an incredibly fun experience and this is just a small part of a title that will also offer a massive single player mode.
Far Cry 4 is coming to consoles and PC from the 18th of November 2014.