8½ is a comedy of guilt, of a life riven by untruths. In a double sense, Guido lives in breach of contract. He compromises the deal he has made with his producers, declaring he has a film in hand when really he has nothing; and, more darkly, he undermines his vow to his wife, by his affair with another woman.
8½ was shot, like almost all Italian movies at the time, completely without sound recording on set. All dialogue was dubbed during post production. Federico Fellini was known for shouting direction at his actors during shooting, and for rewriting dialogue afterwards, making a lot of the dialogue in the movie appear out-of-sync. The title refers to the number of movies Federico Fellini had directed up until that point - six features, two shorts (films #7 and #8) and a co-directed film with Alberto Lattuada, for a total of 8 1/2 films.
The original ending scene of 8½ featured Guido and his wife sitting together in the restaurant car of a train bound for Rome. Lost in thought, Guido looked up to see all the characters of his film smiling ambiguously at him as the train entered a tunnel.
Federico Fellini then shot an alternative ending set around the spaceship on the beach at dusk but with the intention of using the scenes as a trailer for promotional purposes only.