So I just want to say that your game looks absolutely beautiful, its probably the nicest looking chess game I have ever seen, seriously, congratulations on that.
Now for a little bit of a visual hint. The grey boxes where you select difficulty level, they could do with something, the sort of ruin the visuals, perhaps make them slightly transparent.
Now for the bad news. Moving the pieces is tricky and they do not always go where I want, plus there is no undo move button.
That is a huge issue that essentially makes the game unplayable. Which is a pity because otherwise this would be my new default chess game.
For the record I am testing on Zorin Linux so perhaps the window build is better.
Anyway, you said you would swap feedback. This is my game. https://mercstudios.com/play/startalon332/
Love to know what you think.