An excellent film from the uncomfortable opening montage to the bleak final act. I'd recommend it to any horror or thriller fan. The contrast between the bright cheery sunshine against the macabre goings on really is startling. It's a slow build but completely worth the journey.
I wouldn't call this so much of a horror film as suspense, except maybe for the last twenty minutes. It is well made – the innocuous beginning on the Spanish coast, and the weirdness of the island which the married couple visit only very slowly ratcheted up.
Two things that struck me as improbable were the sheer number of children on the island compared with the very few adults we see dead or alive; and the lack of concern displayed by the husband for his very pregnant wife in what rapidly seems a bizarre situation. Perhaps that was meant to be a comment on men.
The film is certainly in period – the husband wears clothes that are very mid-seventies and now seem rather ridiculous. Lewis Flander's performance in this role is adequate. Prunella Ransome is much better as Evie, his wife. It is a great pity that her career was not as illustrious as she deserved. Looking back, I suspect that her rare strawberry blonde 'English rose' beauty was not what producers and directors of the time thought fashionable.