At the Sega logo, press Up, Down, Up, Down, Left, Right, Left, Right, Up, Right, Down, Left. Then, highlight any option at the title screen, hold Start, and press A.
Enter "Hachi" as a name to get a RPO +30 bonus.
Enter "Iyoku" as a name to get a RFR +30 bonus.
Enter "Mizupin" as a name to get a RIC +30 bonus.
Enter "Montaka" as a name to get a RDK +30 bonus.
Enter "Nindri" as a name to get a Dream Hat.
Enter "Taicho" as a name to get a VIT +5 bonus.
Enter "Vjum" as a name to get an Atlus Ring.
Successfully complete the game, then select the character previously used to start a new game in advanced mode. Additionally, when you start a new game file a new character that is a Black Mage will be available.
Use the "S", "E", "G", and "A" in the Temple Of Light to see a "Sega" message.
Just next to the castle is a little building that may be a pub. Outside, there is a blue-haired man next to a fire. Step on the fire and let it damage you. It will not be able to hurt you. Just sit on top of it until your fire resistance is at the maximum.