General Feedback: Great style (I especially like the 3d model in pixel style!), great sounds and clear, satisfying gameplay!
Indept thoughts/feedback: It's a really cute game, currently feels like a nice mini game that you would play in this larger fishing based exploration game. One thing that stuck out was the difficulty scaling. I was getting used to the mechanics and got a hang of it and then I played a song that was at least twice as fast destroying me. It would be nice for some sort warning to what you are getting into so you can practice a bit more with easier songs. And a tiny thing that hampered my experience a little bit was the fishing line, although you could easily see the arrow it did distract me a little bit, so maybe it could be reversed? Fish at the bottom, boat pulling upwards.
All in all I think there really is something here, especially as a game within a game (gwent style) which players put way too much time into. Some slides, extra mecanics and you got something cooking :)
Hope you enjoyed the jam!