Really well polished game. As a chess player I'm offended you didn't implement en passant XD. This is a really cool idea though and I really hope you choose to work on it and publish it. This could be really fun as a multiplayer game! Very well done!
Really good job on the sound design, I'm not even sure how I'd implement procedural music like that, great job! Really relaxing and pretty fun to play, but I can't find any relation to the theme whatsoever.