Bloated as it is with cliche, Alexandre Aja's "Mirrors" really doesn't require much of a synopsis. The film's very core — haphazardly constructed around the fleeting existential angst one feels when looking into a mirror — is worn so thin, so quickly that it is rendered ridiculous almost from the outset. A remake of a 2003 South Korean film, "Mirrors"'s one true virtue is that it provides a glimpse of what other J-horror fare might be like had it been gore-ed up for an R-rating.