What a mess...
But watchable, even beautiful at times. Kinski is Kinski, looking angry or miserable or miserably angry... and mauling the actresses. Venice is Venice and attractively shot. And there are a couple of decent scenes.
The story is, however, almost totally incoherent and it is not helped by editing that occasionally makes it hard to tell what is supposed to be happening. And If Christopher Plummer as a serious but incompetent vampire hunter isn't totally wasted, Donald Pleasence certainly is as a cowardly, hypocritical priest.