In Explicit Ills the actor-turned-director Mark Webber juggles four vignettes of addiction and damage in lower-depths Philadelphia. Two of the cast members shine: Lou Taylor Pucci as a drug dealer who finds a new lover and baptizes himself in substance abuse, and Rosario Dawson as a mother trying to care for her asthmatic son with no health insurance. Webber has a knack for bringing out actors at their showiest, but he palms off too much first-draft sketchiness as ''ambiguity.'' Who is Pucci's character apart from his drug habit? We have no clue. B–

