Very cute and enjoyable! I love the concept it's a very creative take on the "echoes" theme.
If I were to make a recommendation I would definitely say that spacebar being used for both the core game mechanic and menu navigation is quite troublesome as the first time I beat the game I accidentally clicked straight past the end screen. Making these two separate buttons or placing a short timer before the player can click away from the screen would avoid that issue.
Otherwise it was a very relaxing game and I had a lot of fun with it!