If you haven't played it yet, Donkey Kong Country. Some of those secret bonus rooms are real buggers to find.
that game always gave me seizures as a completionist cuz one of the levels in the first world wouldn't give you the !completion mark! even when you found the secret so I would give up
"Salt cures Everything!"
My YouTube: https://www.youtube.com/user/Nirakolov/videos
I just finished a 150 hour plus playthrough where I deliberately tried to do everything, checking every nook and cranny I could find. I'm in the middle of one of my multiple others started and I'm
still
finding things I didn't the first time.