Hi there,
We've gone ahead and removed the flashing background. We absolutely see your point there, and thanks so much for bringing it up. It's been replaced with a repeating pattern, which will hopefully be a bit more acceptable for folx with sensory difficulties.
If it's still too challenging, let us know and we're happy to look into further changes. Alternatively, you can find Glyph on DriveThruRPG here if that proves easier.
We appreciate your interest, and hope you enjoy the game! :)