A very small percentage of individuals may experience epileptic seizures or blackouts when exposed to certain light patterns or flashing lights. Exposure to certain patterns or backgrounds on a screen or when playing videogames may trigger epileptic seizure or blackouts. So the warning goes at the beginning of every videogame manual out there. If you've ever wondered if you're in that small percentage of unfortunate individuals prone to epilepsy, Every Extend Extra Extreme (E4) is a good test. Seriously.