Army of Darkness - The Medieval Dead (15, 89 mins) WATCHING this harmless horror-spoof from writerdirector Sam Raimi, it seems inconceivable that the first film in the series, The Evil Dead, should once have been on the DPP's of *video Campbell plays the chainsaw and shotgun-toting hero projected back in time to circa AD the wisecracks and effects are rather fun. By the time the dead mount assault on a castle, however, the stop motion technique is irresistibly reminiscent of the bygone age of Ray Harryhausen.