“The Shack” (** out of four) was a mushy Christian-themed religious drama about a grieving father (Sam Worthington) whose daughter was recently murdered who receives an invitation from God (Octavia Spencer) to heal and rejuvenate at a holy ground called the Shack. Religious fundamentalists and hard-core Christian followers may find something more of merit here but it’s awfully heavy-handed and not all that moving. Glowing cinematography and Worthington and Spencer’s effortless charisma are bogged down in the corn.