How To Unlock Duck Hunt Duo: Either beat “Classic Mode” with Pichu, complete “World of Light” in 30 hours or spend 1-2 hours playing “Smash Solo Battle”, with rule setting saved to Stock 1, CPU Lvl 1, Damage Handicap On; Next play a stage with a character versus the CPU set to 300% damage. After a win a New Challenger appears, win that match to unlock the new character, then once you return to the stage select restart the game & repeat these steps till you unlock this character