Killzone has yet to get its promised co-op mode but the others listed above all feature co-op play. There's a handful of other titles available to purchase as well at discounts up to 50% off. These price won't last though as the sale ends when January does.

According to its developer, Knack gives more than a subtle nod to classic platform games like Jak and Daxter and Crash Bandicoot. Nothing wrong with that, in our opinion! Keeping everything easy to learn has been a high priority for the team, and from that grew a size-changing robotic protagonist who can absorb relics and elements. Oh, and there are other characters in the story. They can't change size or do anything robot-cool, but they're important, we suppose:

Currently available to pre-order on the PS Store in North America and Europe, Knack and Warframe are two PS4 launch titles with healthy co-op modes that allow you to show off your shiny new system. Japan Studios' Knack is an action adventure game starring the robot Knack in all his parts-filled gloriousness. Co-op is limited to two players locally, allowing one player to control Knack while the other controls a special silver version of Knack. Silver Knack supports Gold Knack by picking up parts from the battlefield and donating them to keep Knack's health topped up, making it an ideal situation for pairs of people where one isn't so video game savvy.

The two minute trailer shows a few quick snatches of the game in action interspersed with dramatic music and characters yelling at each other in Japanese. Knack struts his size-changing parts-becoming-a-whole self in battle, and it looks like some extremely large bad guys are waiting in the wings. The graphics and physics in Knack look gorgeous, something the shaky cam videos from Gamescom 2013 haven't been able to showcase that well.

Only available locally, Knack will support 2-player shared-screen play. Player 1 will be playing protagonist Knack as normal in the game's story while Player 2 will be playing a special silver version of Knack. Silver Knack is designed to support Knack in combat and by picking up parts (which allows both versions of Knack to grow). When Knack gets damaged, he will begin to shrink; however, Silver Knack can donate his parts to Knack to "heal" him.