Play Old Game Boy Games
This hack allows players to play all of the old music and sounds from the original version of "Pokemon Gold," "Silver' and "Crystal." Collect all of the gym badges from the Kanto region. Visit the condominiums located in Celadon City and take the elevator up to the third floor. Once on the floor, speak to the person standing in front of the globe. He will give you an item called "GB Sound;" the key item needed yo unlock the sounds from the original games.
Obtain the National Pokedex
The National Pokedex is an updated version of the Pokedex that players receive at the beginning of "Pokemon HeartGold." It records information from all of the Pokemon in the nation, including those found outside the Kanto region. To obtain the National Pokedex, gain all of the gym badges and defeat the Elite Four once. Visit the S.S Aqua ship in Olivine City and speak to Professor Oak. He will upgrade the Pokedex to the National Pokedex.
Create Special PokeBalls
Make sure you have defeated Team Rocket by making them retreat from their Slowpoke Well base. Afterward, visit Kurt, a man that can be found within a house in Azalea Town. Speak to him and he will inform you of his ability to create special Pokeballs from Apricorns. Hand him any apricorns collected along the journey and wait 24 hours to receive the newly created Pokeball. The color of the Apricorn determines the type of Pokeball that Kurt will create.
Items From Mother
Speak to your mother any time during the game. You mother will offer to save half of the winnings you earn in battle. Accept her offer to save the money. This is useful because it allows you to retain most of your money even when you lose battles. Additionally, your mother will occasionally buy essential potions, berries and rare items for you. Visit the Delivery Man in any PokeMart to receive the purchases that a mother has made.