Get all 151 Pok�mon in the hall of fame.
Surfing Pikachu
Successfully complete the game.
Surfing Pikachu
Successfully complete the game to unlock Surf for Pikachu. To teach your Pikachu Surf, unlock Round 2. Then, get up to the Masterball setting on either the Pok� Cup or Prime Cup (in Round 2). Complete the Masterball setting with Pikachu as one of your active Pok�mon each round (he must be one of the three you choose to battle with). If you lose, you cannot continue (it must be a pure win and the Pikachu may not be part of a registered team or a "Rental"). If you succeed, the game will congratulate you and ask if you would like to replace one of Pikachu's moves with Surf. Select "Yes", then choose the move to be forgotten. The Pikachu will now pull out a surfboard and ride the wave whenever Surf is used.
Mew
Mew will become playable, as a "Rental" Pok�mon, in the Round 2 version of the game. He can only be played in the Prime Cup tournament, Gym Leader Castle, Free Battle, and Mewtwo Battle modes.
Mew in Prime Cup
This trick requires a Game Boy Game Shark and Pok�mon Yellow. First start the game and enable the Game Shark code to catch Mew. Put it first in your line-up, then save the game. Go to the Game Shark screen and enable the code for the first Pok�mon in your line-up to be any desired Pok�mon. Check your stats and it should display your selected Pok�mon's picture, but with Mew's name and information. Save the game. Place the game in the transfer pak and go to the Pok�mon Stadium building. When prompted to select Pok�mon, choose the one that was Mew. When you start the match, the Pok�mon will be Mew.
Mewtwo Battle
Successfully complete all Cups in Stadium mode, and defeat all opponents in the Gym Leader Castle. Mewtwo is the last opponent you will face in both Round 1 and Round 2 versions of the game.
Round 2
Successfully complete the game to unlock a much harder version of the Stadium, Gym Leader Castle, and Mewtwo Battle modes.
Take less damage
Use the following trick when your Pok�mon is receiving a fatal attack, such as when Thunder is used on a Water Pok�mon, to leave you with enough HP to attack your opponent once. When your opponent's Pok�mon begins to use their attack, hold Down + L + B until the energy takes its affect. When the energy leaves, you will have a chance to strike your opponent's Pok�mon. Note: This trick only works between 70% to 80% of the time. This will not work if Pok�mon are totally mismatched, such as when a level 50 Pok�mon is fighting a level 100 Pok�mon.
Inflict greater damage
While your Pok�mon is doing their attack, hold Down + L and repeatedly press A. Then when your Pok�mon attacks, hold Down + L + A until the damage is taken. This is very effective when you attempt a fatal attack. Note: This trick only works between 80% to 90% of the time.
Attack first
Immediately after you choose a move and you want to go first instead of the CPU, hold L and press A. Note: This trick only works about 50% of the time, mostly in the Pika Cup.
Get Pok�mon for Game Boy game
Complete one of the Gym Leader Castles of the Elite Four or your rival to get one of the following random Pok�mon that can be transferred back to your Game Boy Pok�mon game:
Eevee
Hitmonlee
Hitmonchan
Squirtle
Charmander
Bulbasaur
Omanyte
Kabuto
