Sony Japan Studio's PS4 launch title has co-op, a feature that hasn't been trumpeted too much - until now.

On a post on the PlayStation Blog, Sony's Nick Accordino wrote a blog and posted a trailer that details the game's drop-in, drop-out co-op mode.

Accordino writes, "In Knack, our two-player cooperative mode was designed in a way that accentuates the vision for the game. A second player can drop in or out at any time, and control Knack's shiny metallic helper, Robo Knack. Robo Knack has a move set somewhat similar to Knack's, but can donate parts to Knack and heal him with a touch of the Triangle button. If there's a non-gamer or light gamer in the house, this is a great way to introduce them to the world of Knack - just start the game on Easy and drop in from time to time to help them through the game."

Knack allows you to play remotely with the PlayStation Vita and has a tie-in mobile match-three game.