I figured out the achievements and implemented them. As I wrote in the description on the game page - there will be 19 achievements in total. Yes, yes - not 18 ːsteamhappyː
I decided to remake the background for assembling the puzzle, namely:
Make the hint lighter (less noticeable).
Remove the background of the board from showing through.
Perhaps I will add a similar setting (changing the brightness of the hint up to turning it off completely).