The Sega Saturn version of Castlevania: Symphony of the Night has several differences, including more enemies and more areas of the castle to visit.
Below are links to each of the pages showing the exclusive Sega Saturn SOTN material:
Saturn Enemies and Bosses – 18 enemies were added, 2 of them are bosses (Maria Renard and Skeleton Leader).
Saturn Maps – 4 new areas were added which contain the above new enemies. Cursed Prison, Underground Garden, Soul Prison, and Hell Garden.
Saturn Monster Encyclopedia – The Saturn version has a different Monster Encyclopedia which includes the new enemies.
Saturn Characters – Maria Renard and Richter Belmont look slightly different.
Saturn Sprite Sheets – 4 Sprite Sheets from the Sega Saturn version.
Saturn Instruction Manual – The complete Instruction Manual from the Sega Saturn version.
Saturn Case and Disc – The Saturn Case and Disc displays different artwork.