While the game is thought to be as Rondo of Blood port, very few things were actually taken from this game. Levels are completely different and none of them were taken from Rondo. Maria is unplayable character, though given that Rondo didn't felt like a Castlevania game at all, when I played as her, I don't consider it to be a big loss. There are only two alternate levels instead of four. Levels themselves are very linear and doesn't feature alternate paths and alternate bosses. The only Rondo-like "secret path" to the alternate level is in the level 3, where if you fall from the column, you end up in the Alternate Level 4. The game has only two prisoners - Anette and Maria, instead of four. The game doesn't have percentage completion. Art in the game is completely different from Rondo and both Maria and Anette has new sprites. Since the game on the cartridge, there are obviously no animated cutscenes and voiced dialogues whatsover. However, there is no loading times either. In general, Dracula X feels and looks very different from Rondo, for a simple port. It's more like a remake or something.
Graphics-wise the game is very beautiful. It doesn't have the same mood as previous SNES entry - Super Castlevania 4, but it neither looks like its source game, at least when it comes to backgrounds. Backgrounds look like they were taken from the cartoon. They are very detailed and colourful. For the first time Castlevania game was basically combined from different sprites - and it's shows. Backgrounds palette is quite subdued and its clashing with palette of sprites that were taken from the Rondo. When it comes to animations, Dracula X backgrounds have little to no animation and because of that most of the levels (though not all of them) look devoid of life and soul. They are very pretty, but ultimately dead. Hilariously its the same complaint that I had about Rondo's levels, though reasons for this were different. When it comes to special effects - Dracula X is pretty much devoid of them either.
Music in this game was ported from Rondo, few tracks aside. However, Dracula X aded few new tracks - intro theme and awesome tango rendition of the Bloodlines, that used in the credits. Tracks that were ported from Rondo sounds different, since they use SNES hardware and not prerecorded on CD. I think, Dracula X rendition of those tracks are better than in Rondo, since they are more emphasized and sound more louder and clearer, than in ROB.
Gameplay is controversial at best. In general Richter has the same abilities as in Rondo. He can whip only forward, has backflip, and can execute Item Crushes, depending on the weapon that he has in his possesion. However, in Dracula X gameplay was drastically slowed down. And Richter have very different controls and hitbox. His jumping is very strange and awkward. Richter's whip strikes has a lot of weight to them. His backflip is almost useless. Richter's hitbox is strange. When he is standing - it's quite bigger than he is and because of it in some moments you can be hit by enemies, that don't even touch Richter's sprite, that could be very frustrating. However, when he is crouching - his hitbox is miniscule, so even if enemy or projectile directly touch Ricther's sprite, he will not suffer any damage. Also, his whip has not only "backward hitbox", that allow to destroy enemies, that comes from behind, but also "top hitbox".
There are five subweapons in the game - Holy Water, Cross-Boumerang, Daggers, Axes and Stopwatch. Holy Bible, that was introduced in the Rondo, is absent from this game. Like in Rondo, by pressing special button, player can execute Item Crushes. They are mostly identical to the Rondo's.
Levels has nothing in common with Rondo, when it comes to design. There are very linear and straightforward. Some level design are very similar to the Castlevanias on the Game Boy (The Adventure and Belmont's Revenge). In the end, levels reminds about Game Boy dilogy and, yes, NES games. Maybe it was their conscious decision to make Dracula X look and feel like an updated NES title?
In general, games are quite equal. While Rondo wins with amount of content, CDX wins with providing interesting challenge. I'd say those games are centered around very different core ideas. Both games have its strong and weak points. Where CDX is really succeds - its in not making itself tedious and boring. Also, the fact that you need constantly fight with enemies and controls, gives this game not only challenge, but some energy as well. Overall, Dracula X is very odd entry in the series. If one asks me what do I think about this game as port of the Rondo, I'll answer that it is a very bad port that has nothing to do with original game. However, it is a good game in its own right.