Lucky McKee’s directorial debut is epitomized in its conclusion, a passion-charged cobbling of parts designed to pay homage to those it pilfers from. What he serves up is a psycho-horror drama that’s inspired by Repulsion, Frankenstein, and Carrie. It may be shamelessly derivative, but the whole kitschy concoction comes to life through the marvelous performance by Angela Bettis (who played Carrie in the 2002 TV adaptation of Stephen King’s novel). Her May is a rail-thin introvert who’s never been kissed. By day she revels in the gore of her job as a veterinary assistant; by night she confides with the spectral doll her controlling mother gave her as a child. May is downright weird, but she’s endearing in her isolation and her quest for romance. The object of her affection/obsession is a hunky auto mechanic (Jeremy Sisto) who gives her the heave-ho after a kiss turns ugly. Neither does it help that May’s lab mate (a catty Anna Faris) entices her into a lesbian tryst and then dumps her too. What follows is a gory descent into dementia that is both poignant and hilarious. McKee doesn’t know how to balance the two, but he does have Bettis, whose intensity fuses them. (95 minutes)