Classic pot bolier by Corman and AIP. Not the best genre movie the guy has made, but has some nice patterns overall. Shelley Winters is mad in her role and De Niro really looks like an insane soul with his weird baby-talk... if they worked it out properly, maybe it could have been something like "Bonnie & Clyde" of a B-movie realm while now it seems more like a blueprint for Corman's New World Pictures flicks.
An interesting concoction of gangster action and psychological issues, it's easy to see why this is one of Corman's favorites. Ma Barker is a forceful - yet, in a way, pathetic - symbol of motherly love. She does everything for her boys, but doesn't understand the destructive side of her behavior. De Niro is both sad and funny as the glue sniffing junky Lloyd, and Stroud succeeds as the quiet and assertive one.