Off the top of my head it might be 100%ing Action Henk (including all Rainbow medals). Game gets super hard near the end and a lot of casual players straight up don't finish the game (and then complain about it in the Steam reviews).
Possibly some miscellaneous scores/times in various IL games that I've played. Maybe some difficult Mario Maker levels as well.
Hey man, LlamaGuy did encrypt the passwords.
With what? ROT-13?
-CJayC