Before you read the post, be knowledgeable that this game is a GUI-based game where you control a green square traversing levels and avoiding obstacles to beat the game. hink of it like a bare-bones flash game from 2009.
i like the green square itself in the main menu of the game where it moves inside the path on the sides of the main part of the screen
i think you should try making the buttons turn a little darker when you hover over them with your mouse
i think the music also fits well with how simple the game itself looks (if that is what you’re trying to achieve with its looks)
(also i know this is a little offtopic but just out of curiosity what program did you use to make the music?)
edit: also maybe you can try making the “settings” and “other” buttons a smaller than the play button and then center it all in the middle to make they options and the play button feel a little more separate
i dont really have a lot of experience in ui design but i hope this helps a little