Full list of all 12 Phantasy Star II achievements worth 200 gamerscore. It takes around 30-35 hours to unlock all of the achievements on Xbox 360.
You watched the entire in-game credits roll.
You defeated Mother Brain and finished the game.
You defeated Dark Force.
You opened all four dams.
You used a Hidapipe.
You acquired the Laser Cannon.
You reached level 30.
You reached level 20.
You reached the Tower of Nido.
You used an Escapipe.
You spent 1,200 Meseta on one item.
You reached level 10.