The all-but-forgotten Saturn release for this game came more than a year after the Playstation release and had several changes.
Most notably, there were 2 extra stages (one dead-end found at the castle entry, and one short-cut in the middle of the map) that both had unique music composed for those stages, but the same composer as the rest of the game (Michiru Yamane). These 2 stages also exists in the upside down castle, with new music to them too, causing 4 extra stages.
Second most notably, Maria was added as a playable character.
Third most notably, due to the Saturn's graphics engine, some graphical effect were changed; the maching couldn't handle semi-transparency and especially the transformation animations were shortened. The game loaded a bit slower, causing there to be a loading screen between stages.
As the Saturn had an internal clock, the main clock in the room didn't show how many hours you played the game, but instead showed the actual time of the day. There were two rings you could equip, the Sun Stone and the Moon Stone, which augmented your stats between 6 o'clock in the morning and 6 o'clock in the evening and vice versa.
In the main game with Alucard, there was also added a small scene where you battle Maria (she tests if you're strong enough).
And lastly, there is the infamous "Music Card", which, if equipped, will make the half-fairy sing a song if you stand still long enough (I've tested this in the chair in the confession chamber, and it works; don't know if it works in other rooms).
Due to that this release (except graphics) contains virtually only enhancements, it's widely sought after and often causes premium prices for this Saturn disc.