Music test:
Select battle mode then hold R when speaking to the woman on the left side of the screen. Press Left or Right to choose a song number and press A to listen to your selection. Press B to return to the selection screen. Note: Songs must be unlocked during game play.

Rename characters:
When prompted to enter a new name for Felix, press Select(3). Enter a new name for Felix, and you can now enter a new name for Jenna, Sheba, and Picard. Press Up, Down, Up, Down, Left, Right, Left, Right, Up, Right, Down, Left, Up, Select to enter new names for Garet, Ivan, and Mia if playing a non-linked game. A sound will confirm correct code entry.

Revisit last Sanctum:
Hold L + R + Start while loading a saved game.

Revisit towns:
Once you get the Teleport Psyenergy, you can use it on the world map to go to any town previously visited.

Sol Blade:
The Sol Blade can be found at the Mars Lighthouse. It unleashes often and is the most powerful weapon in the game. Only Isaac or Felix can use this sword.

Darkside Sword:
The Darkside Sword can be obtained by taking a Dark Matter to the blacksmith. It is rare to get from him, and is cursed.

All Djinn:
The only way to get all 28 Djinn from the original Golden Sun is to use a password or to transfer your file from that game to Golden Sun 2. All 72 Djinn from Golden Sun and Golden Sun 2 are used to open a sanctuary in the town near the Jupiter Lighthouse, where you can find a Boss called Dullahan who guards the ultimate summon in the game.