Continuity mistake: When Lawrence is watching the weeping angel, just after seeing the Doctor's film/easter egg, he turnes away for a split second. By the time he turns back, you see the weeping angel's face only inches from Lawrence's face. Yet, you then cut to a wide shot were you see the angel's arms outstretched, so its face is about half a metre away from Lawrence's face.
Audio problem: While Billy Shipton is showing Sally Sparrow the TARDIS (in the room where he keeps the abandoned cars), just after he says, '[You] can't even get in it', he rattles the TARDIS' handle to demonstrate. Watch carefully: When he shakes the handle we hear a rattling noise as if the door is shaking, but in fact the door stays rock solid.