This is one of those 'lost classics' and has been resurrected and put back put on DVD by a number of distributors. It was also called 'The Island of the Damned' and that is actually quite good as it is a sort of 'Lord of the Flies' meets 'The Village of the Damned', but without quite the same punch as either of those, but is still good in its own right.
The film opens with a montage of some of the then current world crisis, like the war in Thailand and the crisis in Biafra ' the one thing that the news stories have in common is that it is always the children who suffer. The story then goes that an English couple are on their last holiday before their new baby is born and have decided to spend it on a quiet island four hours sail from the mainland. Fed up of the hustle and bustle of the tourist filled beaches and rousing fiestas and that whole tourist thing. So Tom (Lewis Fiander) and Evelyn (Prunella Ransome) hire a boat and set sail. On arrival they are met by some children, but the ninios are far from welcoming.
After a while they find that everyone has gone away, Tom believes it must be for a festival and so thinks nothing of it, then at the pension where they intend to stay, the phone rings. It is from a German girl begging for help and she sounds desperate' mwaahhh! Yep and then it kicks off.
This really is a great little horror film, but not horror in the slash and scream vein, it is a psychological horror that uses everyday scenarios and turns them round from being a game to being murder. Some of the kids do look genuinely scary and the main characters do a reasonable job of their roles. There has been some criticism of the way Evelyn is presented, but bear in mind this was 1976 and sexism was still pretty rampant, so it is probably quite common for the time. Also this is Spanish but Tom and Evelyn speak for the most part in English, there is a tad of German too but it is all basic stuff and all sub titled.
There is some discussion of the film La Dolce Vita, where a man kills his children to prevent them growing up in a cruel world and this sort of takes that theme and turns it on its' head. There is no real gore in this, some blood and some violence, and the sound quality is slightly below average, but that is forgivable for a film of this age. This is one of those films that will stay with you and I must say I am glad to have finally tracked it down as I remember seeing quite a lot of rubbish seventies films, so this was a real pleasant 'ish surprise.