Mine would have to be Super Castlevania 4 for the SNES.
You are missing a couple, such as the ones on the N64 and the PS2 (Lament of Innocence). My favorite is Aria of Sorrow.
Damn. I didn’t include the N64 and the GB titles on purpose , cause they were horrible 
It’s a tie for me between Synphony of the Night,and Aria of Sorrow.Followed by Lament of Innocence.
SOTN, since all the GBA 1s just try to clone its excellent gameplay.
SOTN is too easy though.
Then what is your excuse for Lament of Innocence. Besides, beauty is in the eye of the beholder. Many don’t like say FF8, but it is one of my favorite FFs. Someone may think that those Castlevanias are the best thing since sliced bread and you are forcing them to vote for something else. Forshame. Although I have heard that the N64 ones were crap.
I just forgot about Lament. It is a great game though.
Four. DEFINATELY Four. :3
The first one.
It was really really really challenging, and I like challenging games. Sometimes.
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