Currently Online 
More that come to mind:
- The fight with/escape from the long-armed woman in The Evil Within where you have to to ignite/extinguish the gas lines. Horribly frustrating when she can one-hit you and here's almost nowhere to avoid her in the enclosed spaces.
- All Ghillied Up in COD4. A boring and drawn out game of follow-the-leader where any deviation from the script is punished by death.
- The secret true final boss of Project Zero 2: Wii Edition. Not only is it basically pure luck as she one-hits you if she gets close enough and teleports around so that if she appears anywhere near you you're instantly killed, but every time you die you're booted back to the main menu and have to load your file and watch an unskippable cutscene. Fucking horrible design, in an otherwise great game.
