Super Smash Bros. Melee/cheats

Unlockables
Dr. Mario: To unlock Dr. Mario, you must complete 1P Classic Mode using Mario at any difficulty/stock and without continuing.

Falco: To unlock Falco, you must complete the 100-Man Melee mode. After you complete that, defeat Falco, and you can play as him.

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.

Jigglypuff: To unlock Jigglypuff, simply complete the 1P Mode game at any difficulty/stock (Adventure or Classic).

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.

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. Alternatively, you can simply use every character as a human player in VS. Mode, and get a challenge from Marth that way.

Mewtwo: To unlock Mewtwo, play in VS. Mode for either 20 hours (Combined VS. Play Time total), or 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.

Pichu: To unlock Pichu, complete Event 37 (Legendary Pokémon). Pichu will challenge you; win and you'll be able to play as Pichu!

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.

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.