Superman II is the 1980 sequel to the 1978 superhero film Superman. It was the only Superman film to be filme by two directors (minus the alternate cut, see below). For this reason the film is surrounded with controversy since original director Richard Donner had completed, by his estimation, roughly 75% of the movie in 1977 before being taken off the project. Many of the scenes shot by second director Richard Lester (who had been an uncredited producer on the first film) in 1979 are refilmed Donner sequences. It was released in Europe and Australia in late 1980 but not in the United States until June 1981. Selected premiere engagements of Superman II were presented in Megasound, a high-impact surround sound system similar to Sensurround.