Errors made by characters (possibly deliberate errors by the filmmakers): In the first movie Hellboy tells Samael, "I'm not a very good shot, but the Samaritan here uses really big bullets." Though after being blown out of the window in this movie, he shoots one of the tooth fairies (which are very small) directly in front of the on-looking crowd. The bullet disappears. No fragments, no injuries to the bystanders. It's possible that his assessment of his marksmanship abilities in the first film was simply false modesty.
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