What is the most difficult video game ever made

i will tell you the most difficult game i played and don't think i am a loser at video games cuz i am an expert ok its called altered beast at ps2 there is a level where you fight a monster that is a bull and a bat at the same time and its element is fire he is too hard i tried more than a month (not continuos of course) but i was losing every time the one who defeated this monster is a hero and i respect him