Answer:
I hide but my head is outside.
What goes further the slower it goes?
What can be measured but not seen?
Look into my face and I'm everybody. Scratch my back and I'm nobody.
I'm a type of pizza that is folded in half before cooking to contain a filling
I can only be played on a windy day
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?