Through this promotion, the PS4 owners who don't yet own the game can try the multiplayer mode
PS Plus members can now begin pre-loading Killzone: Shadow Fall for a special free multiplayer extended open weekend from 12/28 through 12/31, Guerilla Games announced. PS Plus members who don't own Shadow Fall but opt to pre-load and participate in the MP open weekend will also be downloading single-player content (although MP can be prioritized to complete first). Note that while this single-player content will be automatically downloaded, it will not be unlocked during this trial weekend.
In related news, a new update will soon go live and will address many oft-requested features, including the addition of voice chat. Moreover, all additional maps will be made available for free to ensure that the community grows without fragmenting.