I completed this game on the easy difficulty and here is what I can say about it.
The game is pretty good. It's like a very short and dificult version of Rondo of Blood. It gives you an old, good classic'vania feel about. Visuals are pretty and music is wonderful.
Though game has some downsides. Controls are a bit sluggish. And there are questionable enemy placement sometimes (though if I ever do a Castlevania / Castlevania-like game I'll do the same thing, just to piss players of a bit). Bosses almost have nothing to do with Castlevania and could be very difficult, but it's fun to fight with them.
All in all it's a very nice Castlevania-like game with amazing graphics and music. If you are fan of classic'vanias and hard games in general, I think you certainly will like it. If you are more into RPG / "Metroidvania" style then you could be disappointed.