Well I already finished the game and being honest the story has a very good plot, real nice! so this is the first thing that makes you wanna play but then you start the game... know the basics and its just real dissapointing that the game its so damn straight! even though the combat mechanics its nice and handy you just can't play more than 2 hours in a row because it makes you yawn for doing the same thing over and over!.
The game difficulty its kinda challenging, at first sight you can say knack its some kind of childish game with no point in difficulty, nevertheless its pretty though in the hardest difficulty.
So in general lines, knack has a nice plot, good combat mechanics, good graphics but a poor gameplay.