The Coen Brothers have always been critical darlings, but their 17th film, the 1950s Hollywood-set comedy "Hail, Caesar!" has shown an unusually wide gap between critical raves and tepid audience response. This despite a star-studded cast that includes George Clooney, Scarlett Johansson, Josh Brolin, Tilda Swinton, Channing Tatum and Ralph Fiennes.