I like the concept and the presentation is pretty good. The animated characters look a little bit uncanny but cute art style regardless.
I... don't think calibration works very well? My initial calibration gave me +100ms audio latency and +35 video latency, and it became almost impossible to hit Lovely notes so I had to reset both back to +0ms. I don't exactly know how latency stuff works under the hood either so maybe an explanation is needed....
Like others mentioned the charts are accurate to the music but they feel... cluttered? This is especially relevant during sharp curves in the chat, the notes all bunch up and it's hard to see where and what to do. The hold notes aren't very visible, either...
It's a good game! It just needs a lot of work, that's all. Good work nevertheless!