Castlevania 2 Weirdness
Hidden in the ROM of Castlevania 2, there's a hidden enemy that looks somewhat like a Frankenstein monster. Thanks to the Cutting Room Floor for this info.
The cover of Castlevania 2 eerily resembles the cover of an old Ravenloft novel. There's no Simon, but the castle and Dracula look familiar.
Castlevania Games - Castlevania 2 - CV2 Weirdness