Which opera, if any,  Venus and Adonis or Bluebeard's Castle has more acts ?
Bluebeard's Castle Bluebeard's Castle (Hungarian: A kékszakállú herceg vára ; literally: "The Blue-Bearded Duke's Castle") is a one-act opera by Hungarian composer Béla Bartók. The libretto was written by Béla Balázs, a poet and friend of the composer, and is written in Hungarian, based on the French literary tale "La Barbe bleue" by Charles Perrault. The opera lasts only a little over an hour and there are only two singing characters onstage: Bluebeard ("Kékszakállú "), and his new wife Judith ("Judit " ); the two have just eloped and Judith is coming home to Bluebeard's castle for the first time.
The Minotaur (opera) The Minotaur is an opera in two acts, with 13 scenes by English composer Harrison Birtwistle to a libretto by poet David Harsent, commissioned by the Royal Opera House in London. The work, a retelling of the Greek myth of the Minotaur, premiered at the Royal Opera House on 15 April 2008 and was shown on BBC2 television on 7 June 2008. The score is modernistic, and the scenes fall into three types: bullfights; scenes between Ariadne and Theseus; and dream sequences for the Minotaur, in which the creature has the gift of speech. The opera lasts about 140 minutes, not counting the interval.