Castle of Otranto is a mix of colour animation and black and white pseudo-documentary. The animation is an adaptation of Horace Walpole's novel, the documentary concerns a researcher trying to identify the castle where it was set. They complement each other well, and the film moves between the two easily and naturally.
The documentary sections are uncomfortably tight in their framing, crushing the seated interviewer and interviewee so that the tops of their heads are missing, even as their feet remain visible. They seem like the confined giant of the story, unable to move without destruction. The subject of the documentary is treated as delusional, the narrative of the original story is beyond reality. Boundaries remain however, and the film ends with a metatextual shrug that suggests there is nothing deeper at play than a small fantasy, and further exploration beyond this would be meaningless.