Difficult games are difficult for a large variety of reasons. Some test the player's motor skills and reaction time like in Devil May Cry or Ninja Gaiden, while others test planning and problem-solving like Darkest Dungeon or X-COM. Survival horror games tend to ride the line of difficulty and make it more about hiding information from the player, such as enemy placement or the location of resources, and about swift, punishing death as a result of failure.
Source：https://www.cbr.com/pathologic-2-scary-difficult-video-game/
