Hi,
I thought I'd give some suggestions about the quick reference after my initial hour with it.
I found that it was actually confusion how the pictures represent the Pico. They are upside-down when you actually are playing and you have to mentally switch the playing keys from side compared to when you see when you look down on the Pico. So I would actually rotate all the images 180°.
Also, on each page it would be very nice to have the key sequence listed on to get there. Since you're otherwise always going back and forth between the pages just to listen to a sound.
Probably more to come later ...
Geert