Neil Marshall’s anarchic mash-up of early ’80s science fiction and apocalyptic action flicks offers one central pleasure: sitting back and wondering what on earth he’s going to throw at you next. Marshall is no hack, although in this case he seems intent on convincing us that he is. Some of his scenarios are quite inspired, and he goes at them with such enthusiastic gusto that it’s hard to begrudge him the chance to abuse the good will he generated with his superior horror-thriller The Descent and jump off the proverbial cliff. If you decide to go down with him, you might find Doomsday to be a real antidote for Hollywood’s formulaic safety; on the other hand, you might just see it as a big, loud mess. (Hollywood Jewel 16, Waco, TX)