“Mega Lightning” (*1/2 out of four) was a thunderously dull thriller about a group (May Kelly, Maria Taylor, and others) at a house party who become alarmed by the outside stormy weather and move to a nearby house, only to discover there’s a serial killer in the house and they have to decide whether to stay in the house and survive or venture outside and stay alive in the perilous weather. Drab attempt at mixing serial killer and disaster genres with chintzy effects and filmmaking. Hardly anyone’s idea of a mega-movie.