Hotline Miami 2: Wrong Number.
"We added this because some people said that the first game was too easy," Wedin told Polygon. "So we wanted to give them something more. Also, all the players trying to beat the world record or top the leaderboards - we wanted to give them more stuff to be good at."
The mode appears to be level-specific, according to its description. Players that receive a grade of C+ or higher on levels will be able to unlock a hard mode for the stage, increasing enemy resistance and limiting some player abilities.
Though Wedin promised the mode wouldn't be "very hard," the studio has yet to implement the plan, and is unclear as to what features will be included.
For more on Hotline Miami 2: Wrong Number, including details on the game's new character-driven storyline, check out Joystiq's recent preview of the game.