Dark Souls, Battletoads, Ninja Gaiden, and Cuphead wear their difficulty as a badge of pride. They crush souls and spirits alike, and results in a lot of fatigued fingers. Playing them feels like Groundhog Days of death; Live, Die, Repeat, and Repeat!
Of course, theres hard levels like the final stage of the Lost World in Donkey Kong Country 2, the technodrome in Teenage Mutant Ninja Turtles for the NES, as well as the dams in Phantasy Star II.
[Source: kotaku.com ]