7th Saga for Super NES.
Incoming long ass story:
When I was a kid, a friend and I rented the cart from a local video store. We created a save file and used all 3 save slots in case someone overwrites one, we could still beat it. I mean, we were kids, so we didn't have money to pay to rent all the time and parents would beat that ass if there were late fees when they went to rent a movie...
Anyway, even though we would use all 3 save slots, they would STILL get erased, so we would just start over trying to beat it in a weekend, which we never could...
So we saved up some money and the plan was to do a double rental and keep it for 4 days and beat it. Well, this particular game is well knows to have a MASSIVE difficulty spike after one of the bosses in the past, so once we beat that boss, we saved it and went out to grind and figure out where to go next... WELL all of the damn mobs were so massively overleveled that we couldn't even hit them and they would one-shot us.
Needless to say, we never beat that game...
So now, every year, every summer, I load the ROM, load onto the file all the gameshark cheats for max everything except magic, (for reasons you can look up to find out,) and proceed to anally rape this game without lube.
I started doing this in about 2005ish because a friend and I were talking about it so I was like "F that, I want to see the ending." It takes about 5 hours to beat the whole game now since I one shot everything and know, by rote memory, exactly where to go on every map.
So that is the game I have played through the most times in my life.