From what I'm reading so far, Knack is a dud. Everyone is saying the graphics for it aren't impressive and the gameplay gets boring after awhile. Looks like the kiosk are finally hitting retails, but there's nothing on the PS4 kiosk that is showing the power of the system. Sony made a big mistake here.
I'll have to judge it for myself. Everyone has their own opinions on games like these. Hopefully Gamestop or Best Buy now has their kiosk in.