An option saving bug was introduced to the game in the Update [2020.03.28] to support additional options for music and sound volume changing. Now it is fixed in this update. (If it is not working for you after updating the game, please remove the file named "Options.db" at the World Save Location, which can be found at the bottom of the Options tab)
A minor improvement or fixing is added to character jumping to allow jumping with a single press on the space key.