Skins -> 2 subcategories, All skins, 1 Skin

You collect parts for the small robots that follows you, two sub-categories, get a skin (bottom part, middle part, top part) and all skins/parts you need to get 100% then open them all 

You do not need to add them

Oh... ok.
But wouldn't that be just the first level 100% and the full game 100%? Because every level contains one of every part (top, middle, bottom); and to get all the skins you have to collect all the boxes.