Jake Gyllenhaal takes a sledgehammer to his grief in the flawed but well-acted Demolition. It’s the story of Manhattan investment broker Davis Mitchell (Gyllenhaal), whose wife, Julia (Heather Lind), is killed in a car wreck while they’re arguing about a leaky refrigerator. Davis is uninjured and, while waiting in the emergency room’s lobby, has an encounter with a vending machine there that fails to properly dispense his peanut M&Ms. He feels little in terms of anguish over the sudden loss of his wife, even returning to work the next day. It’s that denied bag of candy that really gets under his skin so he begins writing to the vending company’s customer complaint department — long, personal letters that become a narrative device illustrating Davis’ state of mind. On the receiving end of his rants is the vending company’s owner’s wife Karen Moreno (Naomi Watts...