Thanks for playing Jigsaw 360. I produced a video while providing feedback in the community forum and wanted to share it with the rest of you.
This video demonstrates a couple of different approaches to playing that you may not have thought of. It removes the benefit of seeing the black outline that makes it easier to find the missing pieces.
https://youtu.be/2m__zgl7DZk
I'm currently working on the mobile version and have more ideas for improvements to the game in the future.