Biggest disappointments, by game:
Lament of Innocence: Dracula's power stems from glowing magic rocks.
COD: Trevor Belmont, the most powerful Belmont until that point, somehow fails to detect a loud-mouthed man in high heels carrying a giant spear and gets stabbed through the heart.
Castlevania Adventure: Entire damn thing.
Belmont's Revenge: level structure. Plant Castle? WTF?
Castlevania II: No comment.
Order of Shadows: the fact that Sprint is keeping me from downloading this.
Harmony of Dissonance: "damsel in distress" storyline, lack of interesting characters, simplistic gameplay, too easy, gaudy colors.
Dracula X: No comment.
Dracula X Chronicles: character designs, Symphony redesign.
Circle of the Moon: No merchant. Also, hard.
Castlevania 64/Legacy of Darkness: cut material, graphics, camera.
Portrait of Ruin: the reverse levels. However, I actually liked Sisters Mode.
Dawn of Sorrow: Julius mode payoff. Oh, and Arikado screaming "ow!"