Two people have died in Korean Internet cafes since November, and doctors are pointing to dark, smoky, poorly ventilated environments combined with utter exhaustion.

"People who haven’t slept for a long time usually don’t realize how exhausted or stressed they are," said Dr. Song Hyeong-gon, a Korean ER doctor. "Because they are stressed by the obsession with winning the game, they consume a considerable amount of energy. In such a physically exhausted condition, exposure to bright colors or stimulating images on the screen is likely to irritate the cerebral cortex and can cause sudden death."