There's a lot of things I like and dislike about this game.
Starting with the positives, the atmosphere is definitely a highlight. The areas are very distinct and memorable with incredible art direction and some of the best music the series has to offer. The map is also very open so you always have a lot of options on where to go and ultimately get what you need to defeat Dracula. All of this comes together to make the act of exploring very immersive and engaging alongside a moderately fun combat system.
The addition of RPG elements to Super Metroid's formula is a little hit or miss. On one side, having a lot of different equipments for Alucard makes the experience very customizable. On the other, however, it introduces a lot of the same problems RPGs tend to have, which is inconsistent difficulty.
In terms of combat, the general enemy placement starts pretty well made but goes to shit on the inverted castle. There's some areas that have so many enemies that it'd make any classicvania blush. However, due to the RPG elements, I almost never took meaningful damage and it was just a nuisance holding me back from exploring.
And then there's the story. I really liked what they added for Alucard and Dracula's relationship but the way they handled Richter feels insulting. I don't believe anyone with the will necessary to face Dracula's castle and eventually defeat the vampire would be succetible to mind control and ESPECIALLY not to Shaft, the guy he defeated TWICE in Rondo of Blood. As for Maria, she's pretty much there only because of fanservice. She helped defeat Dracula at such a young age and the game wants me to believe that, even with the holy glasses, she wouldn't be able to save Richter? That's just lame to make Alucard being the only protagonist more plausible.
In conclusion, it's a game with a lot of merits that drops the ball in a lot of places that I don't think quite lives up to the legacy of being a direct sequel to Rondo of Blood.

There's some interesting ideas, such as 3D environments, levels being a little more interactable (for instance, the bridge that collapses when you hit it, thus allowing passage) and the game taking place on a more modern setting. However, coming from Super Castlevania IV and Rondo of Blood, this one feels a little unambitious with very little added to the hunters' movesets (and even taking away a lot of what Simon and Richter had previously) but Eric is still pretty fun to use. Overall, it's Castlevania for the Mega Drive and not much beyond that.