In its ongoing efforts to push players toward the PlayStation 4, Sony has added four new games to the PlayStation Network Store, all of which can be pre-ordered right now.

This initiative kicked off last week, as Knack and Warframe pre-order options appeared on the PlayStation Network Store. Today, these games are joined by Assassin's Creed IV, Battlefield 4, Call of Duty: Ghosts and Killzone Shadow Fall. Additionally, the PSN also offers pre-orders on the limited Gold Edition of Assassin's Creed IV, as well as the Hardened Edition of Call of Duty: Ghosts. As you'd expect, these special versions cost more than their standard counterparts, but they also include physical bonus items for truly dedicated fans.

Alongside this news, Sony has also revealed that those who have already pre-ordered current generation versions of Battlefield 4, Assassin's Creed IV or Call of Duty: Ghosts can upgrade their pre-order to the PlayStation 4 iteration of those games for $10. You can find full details on how this process works by visiting Sony's upgrade page, or you can visit the Sony Entertainment Network to place your pre-orders.