The twist that the real Brahms was alive and there was nothing supernatural is what made it work, but The Boy II bizarrely goes out of its way to undermine all that. It posits the real Brahms was nothing but a puppet for the doll, and the character seemingly died following the events of the original.
Curiously, Brahms: The Boy II goes in the complete opposite direction of its predecessor and states that the Brahms doll is unequivocally evil. The end of The Boy hints that the living Brahms might still be alive, but that's no longer the case.
