Here is the full list of all 12 Castlevania: Symphony of the Night achievements worth 200 gamerscore.
Unlock the Inverted Castle.
Obtain the Bat, Wolf and Mist transformations.
Defeat Gaibon and Slogra.
Defeat 10 consecutive enemies using standard weapons without getting hit.
Defeat 10 consecutive enemies using only magic without getting hit.
Defeat 10 consecutive enemies using special weapons without getting hit.
Collect all five familiars in the game.
Defeat Dracula in the Bloodlines stage without getting hit.
Unlock/Cast all eight of Alucard’s spells.
Collect a bank of $100,000.
Explore 200.6% of the game.
Finish the game, including the inverted castle, as Richter.