Pokemon Crystal

Description: Three years have passed since Pokémon Red and Blue. You’re determined to become the best of the best … a Pokémon Master. Don your PokéGear and meet up with Professor Elm to pick a new partner: Chikorita, Cyndaquil, or Totodile. Your objective is to pick off all eight gym leaders one by one. As you collect your Trainer Badges and earn respect among Pokémon and Trainers alike, you will travel through deep, dark caves and across vast oceans and plains. Keep your eyes peeled as you go -- some Pokémon only show up in certain areas and some come out only at certain times of the day and night. And some Pokémon can only be hatched, so you’ll want to match them up wisely to ensure that they produce eggs. Defeating gym leaders is not your only challenge—you also have to fill up your Pokédex and unravel all of the mysteries in the land of Johto.

Cheat Codes

Annons/Unowns
In the back of each puzzle room in the ruins of Alph is a word formed by Annons/Unowns. They require you to do things in order to get into a back room. In one place, you must equip a Water Stone. In another, you must put a Houou/Ho-Oh first in your lineup. In another you must use an Escape Rope. In another you must use Flash. Once in the back room, pick up the items and fall down the hole to find a room with a message about Annon/Unown. Fall down the hole there to return to the Annon/Unown shrine.

Serebii/Celebi
Hook up the mobile adapter. Go to the communication center in Goldenrod City, and read the message on the lockers to the right of the room. They will talk about a present from the future. Leave and the blue-haired nurse will ask you to defeat all sixteen gyms in order to obtain the GS Ball.
Once you have done so, give the GS Ball to Kurt. The next day, he will give it back. Put it in the shrine in the Ilex forest and a level 30 Serebii/Celebi will attack you.

Suikun/Suicune
Find a Suikun/Suicune in three different places (right out of National Park, below the bush by Mount Mortar, and up in Cianwood). Then, go to
Tin Tower, and a Suikun/Suicune will appear to fight you.

Mysterious Channel 13.5
Use your radio in the ruins of Alph to tune into Channel 13.5. You will hear mysterious sounds made by the Annon/Unown.

Hint [Submitted by: Ash]
Start a new game then get the starter pokemon(cyndaquil is best for this)defeat the first 3 gyms the buy 70 pokeballs and 1 repel . then go to bill and he will say 'wow you mustve worked hard' and then he will say'here take these' and he will give you 100 master balls and 251 pokemon

Hint: GS Ball [Submitted by: pokemon master]
To get gs ball go to slowpoke well go to the end and you will find a mew kill it and you go to the dark cave and you will find ash defeat him he will give you magnet and start a new game and you will have gs ball