I don't think I ever sat and played a game for 6 hours in one sitting. I can't imagine doing repeatedly with the same game. And not only that, you have always be precise with your inputs and remember exactly what to do and when to do it.
Also Celeste restarts you on the same screen you die and have unlimited lives. I suck at platformers and had hundreds of deaths on multiple stages but it was still one of my favorite games of last year. Give it a try!