Dr. Mario: To unlock Dr. Mario, you must complete 1P Classic Mode using Mario at any difficulty/stock and without continues.
- Alternative: play 100 vs matches
Falco: To unlock Falco, you must complete the 100-Man Melee mode. After you complete that, defeat Falco, and you can play as him.
- Alternative: play 300 vs matches
Ganondorf: To unlock the evil Ganondorf, complete Event 29. You will then be challenged by Ganondorf; defeat him and you can play as him from then on.
- Alternative: play 600 vs matches
Jigglypuff: To unlock Jigglypuff, simply complete the 1P Mode game at any difficulty/stock (Adventure or Classic).
- Alternative: play 50 vs matches
Luigi: To unlock Luigi, in Adventure Mode, complete the stage with a 2 in the seconds meter 03:12:43 for example. You'll then view a scene where Luigi comes and kicks Mario away so he can fight you with Peach. Finish the rest of Adventure, and the 'Newcomer Fight' will commence.
- Alternative: play 800 vs matches
Marth: To unlock Marth, play Classic mode with all 14 regular characters (not ones you've unlocked). Marth will then challenge you; beat him to gain him as a selectable character.
- Alternative 1: you can simply use every character as a human player in VS. Mode, and get a challenge from Marth that way.
- Alternative 2: play 400 vs matches
Mewtwo: To unlock Mewtwo, play in VS. Mode for either 20 hours (Combined VS. Play Time total)
- Alternative: play 700 matches in that mode. After either requirement is met, Mewtwo will challenge you; beat him.
Mr. Game & Watch: To unlock Mr. Game & Watch, you must complete both Classic and Adventure 1-P mode or the Target Test with ALL characters at any difficulty/stock, regular and hidden that includes Mewtwo. After you do that, you'll be challenged; win this battle.
- Alternative: play 1,000 vs matches
Pichu: To unlock Pichu, complete Event 37 (Legendary Pokémon). Pichu will challenge you; win and you'll be able to play as Pichu!
- Alternative: Play 200 vs matches
Roy: To unlock Roy, complete Classic Mode using Marth at any difficulty/stock. Roy will challenge you; defeat him and you can play as him. Alternative: play 900 vs matches
Young Link: To unlock Young Link, complete Classic mode with 10 different characters at any difficulty/stock. You'll then be challenged by Young Link; defeat him.
- Alternative: play 500 vs matches
|State||Conditions to unlock|
|Battlefield Stage||To unlock the Battlefield stage, complete the All-Star 1-P mode for the first time.|
|Big Blue Stage||To unlock the Big Blue stage, you must play at least 150 matches in VS. mode (without quitting).|
|Brinstar Depths Stage||To unlock the Brinstar Depths stage, you must play at least 50 matches in VS. mode.|
|Dream Land Past Stage||To unlock the Dream Land stage of the past, beat Target Test with all characters, regular and hidden.|
|Final Destination Stage||To unlock the Final Destination stage, you must complete all 51 Event Matches.|
|Flat Zone Stage||To unlock the Flat Zone stage, you must complete 1-P Classic mode at any difficulty/stock with Mr. Game & Watch.|
|Fourside Stage||To unlock the Fourside stage, you must play at least 100 matches in VS. mode (without quitting).|
|Kongo Jungle Stage||To unlock the Kongo Jungle from the N64 version of this game, complete the 15-Minute Melee. I'd recommend using Donkey Kong and constantly use his Down + B move the entire time (thanks to DEngel's Secrets guide, for I used that strategy to unlock this)|
|Mushroom Kingdom II Stage||To unlock the Mushroom Kingdom II stage, which is from Super Mario Bros. 2 on the NES, simply collect a Birdo trophy. The trophy is random, but when you find/win it, you get this stage.|
|Poké Floats Stage||To unlock the Poké Floats stage, you must play at least 200 matches in VS. mode (without quitting).|