“Acceleration” (** out of four) was a muddled action thriller about a determined mom (Natalie Burn) who is told she only has one night to perform vague tasks if she wants to see her son alive after he is held captive by a cold-hearted mob boss (Dolph Lundgren). Co-directors Michael Merino and Daniel Zirilli show some promise and shoot this with style but its routine script and story prevent this from fully “accelerating.” Lundgren sleepwalks through his role and is in the film very briefly; Burn does what she can in the lead