It tries to be a horror, sci-fi, political allegory, social comment, study of a disturbed mind and it succeeds in pretty much nothing of it. Plus, it does what i really hate - tries to pretend it knows more than the viewer with its half-hints and comments impossible to approach and connect. The entire atmosphere is uninteresting, it drags too much. The circular end is expected but it's still one of the best parts.
Beautifully shot, some striking imagery, but in the end becomes a little bit tiring to watch the protagonist chase her shadow throughout the house. Anyway a must see for everyone interested in the psychological aftermath of the Greek dictatorship.