Great game.
There should be an option to toggle two horizontal lines that mark the end of the ends of the angel's vertical trajectory. The reason this option should exist is that nothing is stopping me from drawing them on my screen, and I'm sure they'd improve my gameplay. I do get how that is slightly aesthetically unpleasant, and for example makes sparks at the very top and bottom too legibly irrelevant, but I think the previous argument is irrevocable.