One Upon Light is a monochromatic styled top-down puzzle game with a photophobic protagonist. Trapped in a world of shifting shadows and light, players must manipulate objects in the environment to create a path of shadows to navigate through the levels. As the protagonist journeys through the dark, he discovers clues about his past lurking in the darkness.

"For progress, for humanity… for science! Responsible for many of mankind’s greatest achievements, science has done many wonderful things. But experiments to harness the power of shadow? If it sounds dangerous, that’s probably because it is. Especially if something goes wrong and harmless light becomes the deadliest thing imaginable…"