Luigi appears as the only unlockable character from the Mario universe in Super Smash Flash. He can be unlocked by completing Adventure mode on at least normal difficulty with Mario. He is one of four clone characters in the game, borrowing his moveset from his brother. Like Mario, Luigi doesn't have any real weaknesses, other than his lack of a momentum cancelling attack. This lack of downsides makes his strengths appear event more pronounced, as he has strong match ups across the board, resulting in his high placement.