"Chill" is a good word to describe this. A relaxing experience, and the visuals have a nice, smooth presentation, if that makes sense? I appreciated the undo feature, though having it go back to a previous line would have been good.
Something small that I really liked was that the lines has this kind of tapering to them, making it look nice and hand-drawn. Very cool.
I decided to (only sort of successfully) draw some stuff from my game!