Just like the N64 game, Super Smash Bros Melee is chock full of secrets you can uncover. From hidden characters and stages to simply changing color schemes of existing characters, you'll find 'em all here!

Alternate Stage Music
In Versus Mode, when selecting a stage, place the cursor on the stage you want to play, then press and hold L or R while pressing A. Hold it until the stage starts, and the stage will have a different theme. This trick only works on certain stages, and only after you unlock all the secret characters. When two or more people play, all players have to hold down R.

Unlock Secret Characters
There are 11 hidden characters in Super Smash Bros. Melee, and all of them have a different way of unlocking them in the game. The methods to unlocking each are listed below. (Hint: Play Classic or Adventure Mode on Very Easy difficulty)

Jigglypuff
Defeat Adventure Mode using any character at any level. After defeating the final boss and watching the credits, you will then face Jigglypuff. Defeat it to access it on the player select screen.

Kid Link
Defeat Adventure Mode ten times once using Link and once using Princess Zelda. Kid Link will then appear and challenge you. Defeat him to access him on the Character Select screen.

Luigi
In the first stage of Adventure mode, cross the goal line with a time of xx.x2.xx. You will fight Luigi instead of Mario. Defeat Luigi within one minute, then continue Adventure Mode. At the end of Adventure Mode, Luigi will appear and challenge you. Defeat him to unlock him on the Character Select Screen.

Mewtwo
Play Versus Mode for 20 hours or 700 times. Mewtwo will then appear and challenge you. Defeat him to access him on the Character Select screen.

Pichu
Unlock both Luigi and Falco, or play Versus Mode 200 times. Pichu will then appear and challenge you. Defeat him to access him on the Character Select screen.

Dr. Mario
Defeat Classic Mode as Mario without using any Continues. After defeating the final boss and watching the credits, you will then face Mario. Defeat him to access him on the player select screen.

Falco Lombardi
Play and complete the 100 Man Melee. Falco will then appear and challenge you. Defeat him to access him on the Character Select screen.

Ganondorf
Clear Event Challenge 29. Ganondorf will then appear and challenge you. Defeat him to access him on the Character Select screen.

Prince Marth
Complete 70 Rounds of Versus Mode or use all 14 initial characters in Versus Mode.

Roy
Clear Adventure mode without continuing, or complete Classic Mode without losing a life, using Prince Marth. Roy will then appear. Defeat him to unlock him on the Select Screen.

Mr. Game & Watch
Clear Classic mode with all 24 characters. Mr. Game and Watch will then appear. Defeat him to earn him on the Select Screen.

Unlock Secret Stages
You can also unlock hidden stages to play in Versus or Multi-player Melee Modes. The methods to unlocking each are listed below.

Eagleland: Fourside
F-Zero Grand Prix: Big Blue
Kanto Skies: Pokemon Floats
Planet Zebes: Brinstar Depths
For every 50 matches you play in Versus Mode, one of these four stages will be randomly unlocked. Play 200 full versus matches to unlock all four.

Mushroom Kingdom II: Subcon
Unlock the Birdo Trophy. A new stage will appear on the Stage Select Screen. 

Superflat World: Flat Zone
Defeat Classic Mode with Mr. Game & Watch without losing a life.

Metal Mario Arena
Unlock Mr. Game and Watch, then complete his Event Challenge

Popstar: Whispy Woods
Complete Target Test with all 25 characters.

Dinosaur World: Yoshi's Island
Hit over 1325 feet in the Home Run Contest using Yoshi.

Donkey Kong Island: Kongo Jungle
Finish the 15 minute Multi-man Melee with any character.

Metal Mario Arena
Defeat All-Star Mode with any character.

The Final Destination
Clear all 51 Event Challenges.

Unlock Event Challenges #30- #39
Unlock both Falco and Luigi

Unlock Event Challenges #40- #50
Unlock all of the secret characters

Unlock Event Challenge #51
Defeat all 50 Event Challenges

All Star Mode
Unlock all the secret characters to access All Star Mode in the 1P Regular Mode. In All Star Mode, you have to defeat all 25 characters, and only three Heart Containers and one life to use.

Sound Test
Complete all 51 Event Challenges