There were many “predecessors” of Kong, both ones that direcly inspired it and others that coincidentally were similar. Sometyimes it’s hard to tell the difference.
1.) The Lost World is the most obvious predecessor. It was made in 1925, based on Arthur Conan Doyle’s book, and he was involved at least a bit in it. The same technical tea that would later work on King Kong assembled for this film and did special effects using stop-motion animation and methods of combining that animation with live-action. Willis O’Brien, the lead animator, concveived the ideas independently of others working in the field, and had already made many short subjects not involving live action. Many of his earlier efforts are arguably predecessors, too, and O’Brien himself called his animated ape-man from The Dinosaur and the Missing Link “Kong’s Ancestor”.
The film was butchered after its initial release, and parts were thought lost. Even the Eastman House copy, the single most complete one, is (I think) less tha 80% complete. But a recent effort was made to assemble as complete a copy of the film as possible, using films from seven location around the world. he resulting product is 95-99% complete, and available on DVD, and well worth it.
2.) Creation was a movie about explorers finding an island inhabited by dinosaurs. It integrated live actors with stop-motion animation, and was made by O’Brien and his team circa 1930. The film was never finished, but they used and re-used a lot of elements from it in King Kong, including the T. Rex and the log-rolling scene.
3.) The Giant Pet was a 2-D animated cartoon by Windor McKay, another independent inventor of animation. Adapted from one of his Sunday comics, an episode of “Dreams of the Rarebit Fiend”, it features a creature of indscriminate type (sorta dog-cat-calf) that grows to enormous size and begins pillaging a city. It is eventually attacked by blimps and biplanes (!!) and blows up, all about 15 years before King Kong.
4.) In the book “The Girl in the Hairy Paw” one essay claims that one of H. Rider Haggard’s stories contains a virginal sacrifice to a Monster who lives behind a wall. The monster turns out to be a guy dressed up in essentially a monster costume. I’m not sure which story – I don’t have a copy of the book.
5.) I’ve heard that the structure of Chang, a film made by Cooper and Schoedsack (producers/directors of Kong) echoes the opening of Kong – a mysterious animal is ravaginmg the crops of a village in southeast Asia, and the inhabitants have to find out what it is. Ultimately, the mysterious beast turns out to be a baby elephant.
6.) The scenes in “Gulliver’s travels” where Gulliver, who is tiny compared to the inhabitants of Brobdingnag, is captured by a pet monkey and carried to the top of the palace, a pretty obvious parallel to the end of KK.
7.) the movie Ingagi, made two years before Kong, features an African Tribe that worships a gorilla to whom they sacrifice a woman. In this case, the gorilla is normal-sized. http://www.imdb.com/title/tt0164686/ IIRC, it was marketed as an actual story, filmed as it happened in Africa – a ludicrous assertion.
There were plenty of “lost world” films after Kong, with islands inhabited by dinosaurs, starting with Kong’s seqwuel son of Kong , and the never-released puppet parody The Lost Island. Other examples are Unknown Island (with the least convincing T rexes ever filmed) and The Land Unknown.