Hmm when I launched your game and got into menu it did make a huge work, I mean that singing is really climatic, great job on that. Regarding the game, I almost didn't get the theme, as it took me some time to realise that you were talking in the background, maybe you should add some subtitles that would help in understanding what is said there.
Also great job on particles ;) I would just suggest that when you collect keys, your particles are being destroyed before they end and it spoils their look a bit (maybe there is loop toggled on or just lifetime is too long),
Overall, it was pretty good game, good luck!