Visually it is difficult to fault Damned in Venice and it makes use of a delightful location. However, the first third the movie lacks focus and may well wear down many a casual viewer. Nevertheless, perseverance and a large dollop of patience brings with it it's own rewards and as the film begins to settle into a rhythm it becomes evident that there is a decent enough Rosemary's Baby meets The Omen lurking beneath the surface.
There is some occasional sexploitation to perk things up and decent gore including a priest decapitation by boat propeller which is ace and some pretty grizzly infanticide.
While competent enough, this material would have probably better suited Lucio Fulci in his early 80s horror film prime. Still, it's not awful for what it is.