Welcome to the cheats for Shin Megami Tensei: Nocturne for the PlayStation 2. Below are the cheats.
Debug-mode
Go to a terminal while playing a game, then replace the disc with any other PlayStation 2 game. Exit the terminal, wait for the debug screen to appear, then replace the game disc.
New Game+
Successfully complete the game, then start another game with your cleared game save. You will be able to replay the game with the Demonic Compendium, the ability to change costumes, and no level limit on fusions and summons.