The game wasn't horrible, but getting 5-stars on Hector Hard Mode in Fire Emblem (7) was brutal. It took me an entire summer and like a million resets. *shivers*
If we're only talking about base difficulty though, probably one of the Souls games.
NNID: Zephyr25 / PSN: Zephyr--25 / Switch: SW-4450-3680-7334