What worked:
It's great, and feels like a unique take on Osu. The song is fun and keeps you moving. I really enjoyed it! It's not too mechanically hard to get into, so getting high scores doesn't feel like a chore either! Basing movement only on mouse movement works really well for this making the rhythm portion feel very smooth.
Having the outlines telegraph movements works very well so you can focus on "hitting the notes" as opposed to only having good reflexes and/or memory.
What didn't:
Some of the patterns seem to overlap to the point where I would ignore them (notably some bars that spawned at top of screen) and would be just fine moving from the one before to the next one.
Bugs:
Didn't find any.
Great job!