Continuity mistake: One of the first shots of Switchblade Sam is a closeup of his face, in which the viewer can see he is wearing contact lenses. Kinda hard to believe this homeless-type villian with blackened and missing teeth, old torn clothes and unwashed stringy hair maintains contact lenses.
Plot hole: Towards the end of the movie we see Mr. Wilson peek out from his front porch, surprised to see Dennis biking back home with his wagon carrying Switchblade Sam, tied-up and partly unconscious. Now unless Dennis must have some hidden superpowers or somehow knew how to tweak the laws of physics there is no way that an eight-year-old kid could carry an adult of that size to his wagon let alone easily bike home with Switchblade Sam's weight. Plus being an experienced criminal like Switchboard Sam he may have offered some resistance in being caught doing so much less submit to a mere kid.