Narciso Ibáñez Serrador wanted Tom and Evelyn to speak English to each other throughout the movie. This would add to Evelyn's communication troubles since she isn't able to speak any Spanish at all. However, since the producers feared that the public would get distracted by the subtitles, they made a last minute decision and had both characters dubbed into Spanish for the original version. Ibáñez Serrador has always been very critical of this decision, he felt that it damaged the atmosphere of the film.
Several sequences are homages to Alfred Hitchcock's The Birds (1963), for example, the image of all the children in the island's village square ready to attack Tom and Evelyn, and the final escape from the island.
The film was released simultaneously as "Would You Kill a Child?" and "Death is Child's Play" in the UK. Similarly, American International Pictures released the film as "Trapped!" and "Island of the Damned" simultaneously in the USA.