Considering that this was made in 1972 and is about killer Frogs, I wasn't exactly expecting this movie to be scary, but it's actually really good! Although, "Animals" or "Amphibians" would have been a more appropraite title than "Frogs" because, although there is a massive number of Frogs jumping around the island where the movie takes place, the frogs do not actually kill anybody!...although a lot of other wildlife (mainly other amphibians) do.
Although not gory, this movie was very creepy in several places and actually managed to be quite scary. It is a while into the movie before anybody is killed (about 45 minutes) but the begining is built around suspence and charactor development and does not get boring. The ways in which the charactors are killed off are origional and suspenceful and often quite scary.
A rich millionaire (who hates nature) and his family and three servants are holidaying on a private island that they own. A man comes to the island taking picture of all of the pollution and damage to nature they have caused. The millionaire (sorry, I dont remember the charactors' names) isnt too happy about it but invites the man to stay with him and his family. At first we are just shown scenes of all of the frogs and other animals looking manacing but then the attacks begin and the charactors start die die one by one...
Another reviewer said that there werent many scenes of people being attacked by the animals, but there were quite a few (dont want to give away any spoilers but it was about 6).
Recomend if you enjoy animals-attacking-humans moves or thriller/horror's.