Note: This game is also titled Fire Emblem: Kakusei.
Collect a large number of stat increasing items and gold, then save the game. Recruit a character from the Avatar Logbook, and apply as many stat increases as desired to them. Then, update the avatar logbook for that character. Create a new saved game. Load the first saved game, then repeat the process.
Successfully complete the game to unlock the "Support Log", "Theater", and "Unit Gallery/Sound Test" options in the Extras menu.
Successfully complete Lunatic mode to unlock Lunatic+ mode.