Really clever mechanics and even more clever puzzles ! Reminds me of Return of the Obra Dinn with how you're looking at moments from the past to solve puzzles. It really immerses you into solving each puzzle with rewinding the shadows and moving the light around. Like others have said, i really wished there was sound in the game as it would've really enhanced the experience (not that it isn't great already). I think music and sfx that sound mysterious and whimsical would fit the game, though i don't have any example in mind right now.
One issue i had was with the display scaling. My screen is too small to cover the entire viewport in the game page and the fullscreen button doesn't scale the display to my screen's size. This can be resolved by using the fullscreen button from Unity instead of Itch since Itch's fullscreen button doesn't rescale Unity games for some reason.