I think you’re on the level with a box and a button in the top left. I deliberately made it so there are no flashes, so the player pushes the box instead of aimlessly flashing. To finish the level, simply push the box to the button, and thank you for checking my game out!
Viewing post in The Darkness Remembers jam comments
My number one recommendaiton would be, if you can, calibrate brightness at game start. normally, I find the "adjust brightness until the center image is barely visible" step annoying boilerplate, but I think for a game like this, it's essential. On the level in quesiton, for instance, I could see absolutely nothing without flashes, no box, no button, just pitch blackness, on my monitor anyway. But your game's vibes are still pretty much immaculate, IMHO, which counts for a lot.