Really nice concept and execution! Could definitely see this being built out into a full game! Nicely done! I did think the light physics were a little counter intuitive and sometimes wasn't clear how much light was needed to hurt the shadow but all in all really well done! Really great interpretation of the theme.
Thanks, I've been experimenting with ways of better communicating how the light controlling shadows works (its actually a bit above the map to prevent shadows from going on forever). Its definitely the most common issue I've heard! The only part of the Shadow that actually gets checked is the dead center.