unfortunate flaw
Not necessarily a fatal flaw, but one that detracts from my enjoyment: too much characterization for "the monster" of the piece.
The original movie quite fittingly made Janos Skorezny a dark, mysterious shadow-creature of the night, whose only personal history was cited from old records. Not so the Night Strangler, who at the end is not only shown far too much, has a much more "modern" history, but also has a dialogue with Kolchak that is much too aromatic of pathos. TOTALLY wrong approach:
Janos Skorezny did not get to have - did not NEED to have - a voice in the original movie; he never had to explain himself as being just a poor cursed creature, driven by simple survival to utilize human blood toward that means. Not so the Night Strangler, who, unlike his vampiric counterpart, gives Kolchak a ten minute monologue on who he is and why he must do what he must do. He even basically gives Kolchak a tour of his underground home. Not to mention that, as it turns out, the Strangler ... Is Quite...Mad: more pathos, as he tragically if not touchingly consults his mummified wife and family before spilling his not-so-baffling secrets to Kolchak. Mystery: gone. Horror: diminished. Villain: too fully revealed.
Not to mention that the notion of a chemically-immortal Civil War era alchemist simply cannot hold a horror candle to the suggestion of Vampirism's ancient and archetypal menace.
Not to mention that the film's early portraiture of the Night Strangler gives away the reason that the name "Richard Anderson" is listed in the opening credits. We know what the Strangler looks like even before he appears in the last fifteen minutes, and by God, he looks like Anderson; another mystery dispelled well before the climax. Richard Anderson does deliver a superlative performance, but it unfortunately functions as a complete deflation of all that went before it.
When a horror film shows too much of its monster, has the monster explain itself to its human nemesis, and gives the audience to understand the monster in much-too empathetic terms, the film has crossed the line from strong horror to semi-schlock. The only saving graces that buffer The Night Strangler from being total schlock are the strong performances, witty dialogue, and (at least some) on-location shooting in the real Seattle.