Nope, you are righ! Akumajo Dracula X: Nocturne in the Moonlight for the Sega Saturn is a slightly enhanced version of the Playstation classic of the same name.
When they ported the classic vampire killing adventure over to the Saturn, the added two new levels, new music, made Richter playable from the beginning, and added Maria Renard as a playable character among other things.
Unfortunately, they added more load times, took away most of the transparancey effects, and added some slowdown.
Do not let those bad things get to you, though, as the game is still excellent and an all-time classic. If you can get it for a good price, pick it up but if the PSX version is the only one you can get your hands on, that is fine too.