Unlock GB Tower Secrets
To get your Gameboy games to play at a higher speed at Game Boy Tower, defeat either Gym Leader Castle or all Stadium Cups in Round One. This will give you the Doduo sticker for GB Tower, allowing you to play Gold and Silver at double speed. If you beat the Castle or Stadium Cups in Round Two, the Dodrio GB Tower will be unlocked, allowing you to play the Gameboy games at Hyper Speed.

New Start-up Screens
Beat all of the cups in Stadium mode and you'll unlock a special title screen. Do it again in Round Two, and you'll see yet another start-up.

Fight Your Rival
Once you beat all of the Cups in Stadium Mode and all of the trainers in Gym Leader Castle, you will unlock a special Rival Cup in the lower right corner of the main map. Click on it to take your team against the mega-tough trio of Mewtwo, Ho-oh and Lugia.

Get Rare Pokemon
Beating the Rival Cup the first time will yield a rare Farfetch'd Pokemon with Baton Pass. The second time you beat the Rival Cup (Round 2), you'll be granted a Gligar with the Earthquake move. Both of these moves are not normally learned by these Pokemon, making them super useful and very rare.

Harder Mini-Games
Challenge your computer opponents to a Hard seven-coin Mini-Game battle. If you win the game, another difficulty level will be unlocked: Super Hard.

Trading using Pokemon Stadium
What you need:

- Two Pokemon game cartridges
- Pokemon Stadium 2
- Transfer Pak
- Some captured Pokemon
How to do it:

1. Go to the Pokemon Lab in Pokemon Stadium 2
2. Go to the PC and select Pokemon
3. change the box to one of the N64 boxes
4. Put the Pokemon you want to trade into the N64 box
5. Save and quit and turn off your N64.
6. Put the other Pokemon game in the Transfer Pak
7. Repeat steps 1, 2, and 3, then put the Pokemon that are in the N6 4box into your party.
Note: there's one catch: the pokemon that are supposed to evolve when traded don't evolve.

Get More Knowledge at Pokémon Academy
Once you have finished all the classes and passed all of the tests and won the school battles (beating the Elite Class), more information will be available at the Library, including all Items available in all of the Gameboy Pokémon games.

Rent Celebi
To rent Celebi, you will have to open up Round 2 by beating all the cups in Stadium Mode, defeating all the trainers in Gym Leader Castle, and taking care of your rival. Once you open up Round 2, you will be able to rent Celebi.