Deadly Stages, Marc Castle and Mark Finley's genial comedy opening today at Theater Row, is a spoofy, affectionate homage to low-budget movie murder mysteries that might have been third on the bill at the local drive-in in the 1950s. And despite the production's somewhat ramshackle appearance, it is full of little surprises, inside jokes, catty repartee, and just-this-side-of-campy performances by a cast of Equity ac…
