The last three achievements require completing hidden levels. On the initial interface, click the "i" in the title "Ondrian" several times until "The Man Behind the Scenes" changes to "Behind the Scenes." Click "Behind the Scenes" to open three hidden levels.
shadow in sunlight
Thanks for sharing the guide, all achieved~
distant memories
Is it enough to play Color of Return ten times? Do you have to pass every time in these ten times?
Walker in the clouds
Where did the last achievement come from?