If White Face catches the player during the game of tag, a text file named "got you" that says "slowly" is created. As shown right after the player escapes the tag area, White Face could pop out from nowhere at high speeds anytime it wishes, so in the text file it is making fun of the player for being caught while it is not even serious.
"The sound predicts its arrival". Sure, during the game of tag White Face will start roaring when it is close, but was it making any noise when it first appeared behind the cell? Or when it leaves trails of blood right behind you or when it welcomes you into its room?
During the third stage, the fog is white, initially, this makes the level appear relatively less scary, because although the view distance is still just as short, the white fog makes everything seem to be under daylight. After acquiring one of the keys, the fog turns black, and you can see White Face outside, watching you. Eventually, it dawns on you that White Face was always there, watching you, and you simply didn't know. Once you realise this, the next time the fog turns white can actually be very scary, as you realise you can no longer tell where he is.