PlayStation Plus subscribers will be able to try out Killzone: Shadow Fall‘s multiplayer component for free over the weekend of 28th to 31st December 2013, without having to purchase the full game. It’s effectively a multiplayer trial, but gives you a good idea of what the game is like, and maybe even persuade you to but the full version.
The play-as-you-download feature will let you download the multiplayer portion first, but you’ll effectively have to download the entire game, with the single-player component remaining locked until the full game is purchased – the single-player component won’t be available to play during the Open Weekend.