SOTN is the best in the series, so you picked a good one to start with.
The sad part? You will be disappointed in the rest of them, as you are playing the best the series has to offer.
The other ones are good as well (well, for the most part) but they are a step down from SOTN.
i see what your saying, i played castlevania: rondo of blood which was unreleased in america but is INSANELY good. the whole game is pretty much the beginning part of SOTN with richter belmont
i really like how non-linear the earlier games are