Thanks for the detailed feedback!
Sorry I couldn't make the stream this morning, if you want to give it another try you can change the controls in the options menu. I also use right hand for the drum and left hand for movement and I agree I should have made this the default.
There are also more options like audio offset and some assist options in case you want to make the game easier (or even fully automated, in which case the game will pick the hardest level to show off haha)