Masocore (a portmanteau of "masochism" and "hardcore") is a theoretical video game sub-genre specifically designed to frustrate players by combining complex game mechanics with intense, seemingly impossible difficulty in special "trial and error" scenarios. Characteristics of masocore games include infinite lives (forcing players to retry sections of the game over and over in order to proceed), twitch gameplay, and confusing (and often conflicting) goals. Most popular in postmodern indie games, masocore games usually fall under the 2D platformer genre (though some bullet hell games often double as masocore games).
One of the most popular (and difficult) indie masocore game is I Wanna Be The Guy, which parodies popular retro games while including intense platforming challenges that require near-pixel perfection and heavy memorization to complete.
Masocore is not to be confused with games that are difficult but do not include infinite lives or "trial and error" scenarios (such as the Mega Man franchise, which include difficult jump-related obstacles). Some masocore games such as Seven Minutes are designed around old gameplay concepts of their given genre that are mixed together in a way to exacerbate the level of challenge.