Super Smash Bros. Melee

Battlefield Stage
Complete the All-Star 1-P mode for the first time.
(Thanks to Yaziiconner1@aol.com)

Dream Land Past Stage
Beat Target Test with all characters.
(Thanks to Yaziiconner1@aol.com)

Final Destination
Beat ALL the event mode matches.
(Thanks to nicholasduncan@webtv.net)

Flat Zone Stage
Complete 1-P Classic mode at any difficulty/stock with Mr. Game & Watch.
(Thanks to procrastinhater@hotmail.com)

Get One Life Back
If you're playing in Survival mode in Team Battle, you can gain 1 life back if you die. When eliminated, press Start button and you gain 1 life back. Note: only works when cpu or other player on your team is still alive.
(Thanks to mythbusters123@yahoo.com)

Kongo Jungle Stage
Complete the 15-Minute Melee.
(Thanks to procrastinhater@hotmail.com)

Mushroom Kingdom II Stage
Collect a Birdo trophy. The trophy is random, but when you get it, you get this stage.
(Thanks to procrastinhater@hotmail.com)

New Verses Mode Stages
For every 50 verses matches you fight, you will unlock one of 4 new arenas: Brinstar Depths (50), Fourside (100), Big Blue (150) and Poke Floats (200).
(Thanks to HotD)

Starfox Secret Taunt
On any Starfox level with Fox or Falco, on your d-pad you must press the taunt button fast multiple times. Stand in one place where your enemy will avoid you. Your character will salute and then you can hear the Starfox team talking. If the taunting button doesn't work, on your d-pad, press left and right multiple times.
(Thanks to LunaStarlight14@msn.com)

Unlock Secret Characters
Dr Mario: complete classic mode with Mario without using a continue.
Falco: complete the 100-man melee match in stadium mode.
Ganondorf: complete event 29 in event mode.
Jigglypuff: complete classic mode once with any character without using a continue.
Luigi: complete the mushroom kingdom stage of adventure mode with the fourth digit of the timer as a 2. (xx:x2:xx)
Luigi: complete adventure mode without using a continue.
Luigi: play 800 verses mode matches.
Marth: play one complete versus mode match with each of the 14 original characters.
Mewtwo: play versus mode for either 20 hours or 700 matches.
Mr Game & Watch: complete classic mode with all 24 of the other characters.
Pichu: complete event 37 in event mode.
Roy: complete classic mode with Marth.
Young Link: complete classic mode with 10 different characters.
(Thanks to HotD)

Unlock Marth (alternate method)
Beat Classic Mode with Peach, using no continues.
(Thanks to jcuratola@comcast.net)

Unlock Mr Game and Watch (alternate method)
Beat target test with every character.
(Thanks to smallkl@muohio.edu)

Unlock Pichu (alternate method)
Play 200 matches of melee.
(Thanks to jcuratola@comcast.net)

Unlock Yoshi's Island
To get Yoshi's Island, just make a record of 1,200 yards of sandbag contest with Yoshi.
(Thanks to javierpatinojpd@yahoo.com)