When Graham escapes the police through a window, the bottom half of the window is too easily damaged by just closing it on his arm and it breaks apart and falls away. However, the next shot from outside, the window appears largely intact.
In a poorly-done special effect, the lightning bolts across the sky appear in front of the limbs of a tree near the camera.
Near the beginning of the movie, Inspector Davis asks someone from his office what a "cryptographer" is. It is inconceivable that a Scotland Yard Inspector wouldn't know that.