The Danish director Christian E Christiansen's witless, badly acted thriller is a throwback to the early 1990s. It signals every punch it throws in telling the tale of an innocent first-year student at a Los Angeles university sharing her college room with a manipulative psychotic fellow freshman. Someone once remarked to Ernest Bevin that Herbert Morrison was his own worst enemy. "Not while I'm around," snarled Bevin. By the same token I would say of the claim that The Roommate is the worst film so far this year, "not while Mars Needs Moms is fresh in our memory".