Thought i encountered a bug until i figured it out. Effective horror! I think the light puzzle solving is very satisfying, i think if you wanted to you could build a larger game around this mechanic. Think like a restaurant/shop game where you expand your part options. Maybe a cookie clicker type game where this more active monster matching component is the twist.
Regardless, it's a satisfying little joy. Thank you for sharing it. I hope you keep creating, whatever it is that sparks your interest.