Since it is both a low budget film and a silent film recreation, it uses low grade effects, such as a giant monster that is quite obviously an art project and a scene out at sea that is clearly on a paper ocean and backdrop. Some people would probably find this highly distracting, as many look back at old films and low budgets with a scrutinizing eye at the lack of sophisticated technology. Yet, we never critique a play for little to no effects, but see them as more of a bonus part of the experience.
I thought the Historical Society actually achieved a perfect atmosphere with the resources available. There were moments of suspense in which I was truly terrified, such as when the protagonist dreamed of the Old One, Cthulhu, slumbering in an ancient city we caught mere glimpses of the horrorific abomination.
When I see the big budget effects in mainstream movies, I am often not impressed as it doesn’t seem to me anymore realistic than the art-project Cthulhu and that worked well for movie-goers in the 1920’s. Much like theater or any form of fiction, a movie is about the willing suspension of disbelief as we allow ourselves to believe that the art-project Cthulhu is a true eldritch creature or that the CGI monster in Cloverfield is a living beast from the sea. If atmosphere, actors, or direction can pull us into the story, it shouldn’t matter if the producers have the cash to create that alien instead of a paper machete creation.