Interesting how the game tries to play with the concept of power fantasy on its design but fails ultimately.
Knack always starts small/weak and keeps getting bigger/stronger and gaining different powers (incorporating elements) throughout the levels, which makes a compeling idea in how the player has to deal with the adversities with small-knack (bigger focus on the enemies moves and attacks, as you can die easily) and later with bigger-knack (just smash).
This constant variation in the way the player interacts with the world should be interesting enough, but rarely is, as Knack moveset is so limited (one punch and one 'special') no matter his size, that there's no difference in how the game can be played, just dodge, attack and repeat.
Some enemy attacks are more creative and can complement knack's moveset in a way that makes the combat work, but you can count these instances.
In the end, Knack is such a simple game that it's hard to not think this was halfway in development when released.

I was expecting that a console launch game directed by the lead architect on the console itself would use more of it's functionalities, half of the buttons on the controller aren't even used.