Silent Hill 3 has a lot of standout moments, but arguably the game's scariest sequence occurs in a mirror-filled room at Brookhaven Hospital. Heather sees her innocent reflection moving around in the mirror across from her.
I've just played Silent Hill 3 for the first time, and it is the scariest game I've ever played. I'm no connoisseur of horror games, but I've played my fair share. Resident Evil, Outlast, Alien Isolation, to name a few.