Universe Mode is a difficulty setting in the Star Ocean series. In this setting, enemies are made harder to defeat due to increased HP, MP, and other stats.
First Departure was planned to have Galaxy and Universe modes during development, but seeing as how the original Super Famicom version of the game did not have such difficulties, the modes were "dummied out" and are only "accessible" via hacking the game (i.e. CWCheat).
To unlock Universe mode, 45% of the Sound Collection must be unlocked.
Unlike in The Second Story, the player must defeat 2000 enemies in a single save to unlock both Galaxy and Universe modes.
To unlock Universe Mode, 75 out of 300 Battle Trophies must be acquired. There are certain BTs that can only be acquired in Universe mode (i.e. defeat Luther or any of the post-game bosses on Universe Mode in x minutes, without taking damage, etc).
Universe Mode reappears in the series' fourth installment. To unlock Universe, the player must beat the game on Galaxy mode.