Thanks for trying it out, and for the encouraging words! I wanted to add some on-screen controller help, but I failed to get it finished on time... I will certainly be adding to it in the future though! And, as far as the controls go when you're in music mode... think about WASD as the d-pad on a controller, and Up, Down, Left, and Right as the face buttons (unless you're using a controller, in which case, picture the d-pad as the d-pad and the face buttons as the face buttons). The left side is your lower four notes, and the right side is your upper four notes. In order, the notes go bottom to top, left to right, so the bottom button is the lowest note, then left, then right, then up. So, on keyboard, a full octave is S, A, D, W, Down, Left, Right, Up, and on a controller it's Down, Left, Right, Up, A, X, B, Y. The triggers change octave, and the bumpers change tempo.
I hope that helps you enjoy it a bit more, and in the future I'll definitely be adding on-screen control indicators!