Unlock Paper Mario Trophy:
In Homerun Derby mode hit over 1500 feet.

Unlock Pikmin Trophy:
Insert a 'Memory Card' which has a saved game from Pikmin and when you start the game the Pikmin trophy will be available.

Wave Race: Blue Storm Trophy:
Insert a 'Memory Card' which has a saved game from Wave Race: Blue Storm and when you start the game the Wave Race: Blue Storm trophy will be available.

Unlock Luigi's Mansion Trophy:
Insert a 'Memory Card' which has a saved game from Luigi's Mansion and when you start the game the Luigi's Mansion Trophy will be available.

Unlock Alternate Trophy Background:
If you zoom in on a trophy and press 'Start' the background will change.

Unlock Pichu:
Complete Legendary Pokemon Event 37 and defeat Pitchu when he challenges you.

Unlock Dr. Mario:
Complete Classic in 1-P mode using Mario with any difficulty and without continuing.

Unlock Jigglypuff:
Complete Adventure or Classic in 1-P mode in any difficulty.

Unlock Mewto:
Complete 20 hours of combined Vs Time total then defeat Mewto when he challenges you.

Unlock Luigi:
Complete Adventure mode with a 2 in the seconds metre like for example; 04:32:34. You will then view a scene where Luigi kicks Mario away so he can fight you with Peach. Defeat them both to unlock Luigi then Defeat Luigi.


Alternate Character Unlocks
Unlock characters by playing a certain number of vs. Matches.

Jigglypuff:
50 vs. Matches

Dr. Mario:
100 vs. Matches

Pichu:
200 vs. Matches

Falco:
300 vs. Matches

Marth:
400 vs. Matches

Young Link:
500 vs. Matches

Ganondorf:
600 vs. Matches

Mewtwo:
700 vs. Matches

Luigi:
800 vs. Matches

Roy:
900 vs. Matches

Mr. Game & Watch:
1,000 vs. Matches

Mushroom Kingdom II (Super Mario Bros. 2):
Get Birdo or Pidgit trophy from Super Mario Bros. 2

Superflat World: Flat Zone (Game & Watch):
Unlock Mr. Game & Watch and defeat Classic mode with him

Battlefield:
Defeat All-Star Mode (secret mode) with any character

Final Destination:
Clear all 51 Event Matches

Planet Zebes: Brinstar Depths (Metroid):
Play 50 Vs. matches

Eagleland: Fourside (Earthbound):
Play 100 Vs. matches

F-Zero Grand Prix: Big Blue (F-Zero):
Play 150 Vs. matches

Kanto Skies: Poké Floats (Pokémon):
Play 200 Vs. matches

Yoshi's Island (Classic N64 Yoshi Stage):
Hit 1,323 feet (or more) in the Homerun Contest with Yoshi

Kongo Jungle (Classic N64 DK Stage):
Finish 15-minute Melee with any character (Tip: use Donkey Kong with his down+B ground slap)

Dream Land (Classic N64 Kirby Stage):
Complete Target Test successfully with all 25 characters

Play as Falco Lombardi:
To unlock Falco Lombardi successfully complete the 100 Man Melee or play 300 versus mode matches.

Play as Gannondorf:
To unlock Ganondorf successfully complete event mode #29 (Triforce
Gathering) or play 600 versues mode matches.

Play as Roy:
To unlock Roy successfully complete the game with Prince Marth in Classic mode or play 900 versus mode matches.

Battlefield stage:
To unlock the Battlefield stage successfully complete All-Star mode.

Play as Falco Lombardi:
To unlock Falco Lombardi successfully complete the 100 Man Melee or play 300 versus mode matches.

Play as Gannondorf:
To unlock Ganondorf successfully complete event mode #29 (Triforce
Gathering) or play 600 versues mode matches.

Play as Roy:
To unlock Roy successfully complete the game with Prince Marth in Classic mode or play 900 versus mode matches.

Battlefield stage:
To unlock the Battlefield stage successfully complete All-Star mode.