From the same producers and director of Die, Monster, Die! comes another loose Lovecraft adaptation. This time, Dean Stockwell plays a mysterious pagan/hypnotist dude who is trying to get his hands on the Necronomicon to enact an ancient, most likely terrible ritual.
Some of the major names in horror in the 60's (American International and Hammer most notably) had a little trouble adjusting to the 70's. I'm not sure if they were trying to go for a more modern feel, if they were running low on funds, if their best talent jumped ship, or some combination therein, but they starting losing a bit of their classic, gothic flavor in favor of a less stylized, more naturalistic vibe. You started losing the orchestral scores in favor of weird jazz improv bullshit, more often the setting would be moved to present day, and the rich, shadowy cinematography turned into a cheap, less colorful, flat look more akin to low budget American indies.
The Dunwich Horror seems to have one foot in each era. It's an adaptation of a classic horror story, much of it is set in a lavish mansion, it's got some of the trippy special effects a la Corman's Poe adaptations. But it also looks cheaper, more amateurish, with less interest in atmospherics and a slightly more tawdry edge to it, what with its cult orgies and all.
The story never really heats up, and I think part of the problem is that there isn't really a central character for the audience to identify with. The leads are Stockwell as a wizard (or whatever) and Sandra Dee as his love interest/victim. Stockwell is great as the calm, eerie but also charming sorcerer, but it's never clear how sympathetic his character is supposed to be. He is ostensibly the villain, but his character is also persecuted by the other townspeople because of his religious beliefs. So you kind of feel for the guy, even though the townspeople are kinda right not to trust him and he ultimately is the villain. Dee should then theoretically be the one we are concerned about, but she's so passive (she spends pretty much the whole movie under Stockwell's spell) and lacking in personality that it's hard to give a shit. The good guys are some historian types who realize what Stockwell is up to and try to stop him, but they mostly seem to take a backstage to the rest of the action.
It all falls apart near the end. Right when the tension should be building, the story loses focus and cuts around between different scenes that feel disconnected despite the fact that they are all supposed to be coming together. And the final battle is so hilariously abrupt and arbitrary that it retroactively wipes out any sense of danger that the film might have engendered at that point.