Persona 2: Eternal Punishment Codes -

Teleport:
Use the map, choose a location, then press Select to teleport there immediately regardless of the different stories. Note: This does not work in some areas, such as locations where your party is all able to talk to, and no enemies. The map will show that area as Green when you are in that room.

Full map access:
Press Start(2) when using the map to get the full map. This also works with the "Teleport" trick and includes different stories/levels.

Increase Persona rank:
During battle, go to "Strategy" on the menu and select "Action". Choose any character whose persona you want to rank up. Then, go to "Status". While you are at the status menu of the character, hold R1 to instantly rank up your Persona to 8. Press L1 to decrease the rank. You can now access all the spells the Persona would obtain at rank 8, but you cannot get hidden spells gained by mutation.. If you want to rank up several Personas at one time, just change the Persona using "P.Change" and repeat the whole process.

Debug menu (pre-release version):
Hold Select + Start + L1 + R1 during game play to display a debug menu. Press L1 + R1 + L2 + R2 + Start + Select at the debug menu to advance to the next mission. This may also be done during Boss fights.

Alternate spells (pre-release version):
While in a battle and choosing a Persona spell, highlight any spell and press R1 or L1 to scroll through the spell list. This will even allow you to cast spells you have not learned yet. Note: This also includes spells only found in enemies and special characters -- choosing these spells may cause the game to freeze.