The answer is: all of the dark. In one scene, our hero is sent on a mystical acid trip straight to the 10th circle of hell. Things start out pretty tame, with Link floating calmly through an endless black void.
The riff from "Sunshine Of Your Love" in now playing in your head.
Next, we see Link hanging out with his childhood friend, Ilia. Both of them are happy and laughing ... until she turns around and waves a blade at Link like she gonna cut him up real bad. Also, she seems to have misplaced her pupils.
"YOUR MOTHER SUCKS LON LON MILK BOTTLES IN HELL!"
Ilia screams and drops the knife, and next thing you know Link is alone and he's the one with all-white eyes. What in David Lynch's therapist's name happened there? We don't have time to consider the disturbing implications, because this is when three dark-skinned, red-eyed Link doppelgangers show up and turn you into dust.
After giving you the most half-assed Heil Hitlers ever.