Complex sentence: The film was mostly shot without a screenplay, with ad-libbed lines, and production starting having only the outline and the names of the protagonists-keeping the Western theme, Wyatt was named after Wyatt Earp and Billy after Billy the Kid.
Split into simpler sentences: The film was mostly shot without a screenplay, with ad-libbed lines, and production started with only the outline and the names of the protagonists. Keeping the Western theme, Wyatt was named after Wyatt Earp and Billy after Billy the Kid.