How big a part is co-op/multiplayer for this game?

[The Chosen One]

As title.

[Lizard Smoothie]

Hi! I'd say the co-op matters much as you enjoy playing with other people.
Shape of Dreams is designed to be enjoyed to its full extent whether or not you're playing solo or co-op, but when you do play co-op, we have several system in place to ensure you'll have a good time :)
Please let me know if you have any more questions!