Terrific job combining the theme and the genre of the rhythm game!! It's so refreshing to see this unexpected combination. I also love how your story develops creatively, covering many different atmospheres. congrats for this huge amount of work!
When it comes to the repetitive nature as some others said, I think it can still depend on the type of the rhythm game. While it would be a bit too repetitive indeed for games in competitive nature(like bemani series), something with a more emphasis on the story telling(like rhythm doctor?) could work in my opinion. You could even use the repetitions to your advantage, developing the story so the player don't have to be uber concentrated on the gameplay all the time while missing what's happening. And your story deserve that attention!