Odd bug in this one, I didn't even realize it was a proton issue at first. For some reason, the framerate of the rhythm bar itself is way lower than everything else in the game. It'll make playing on higher difficulties a problem.
EDIT: Seems to have resolved at some point, not entirely sure when.
Nothing extracted yet.
Compatibility Report
System Information
I confirm:
steam-514310.log
Symptoms
The game seems to be playable, but:
interpreted as 
interpreted as 
interpreted as 
interpreted as 
On dualshock 4 are messed up buttons
Reproduction
Just play in the game with dualshock 4.