Plot hole: When Jack The Ripper checks his watch before confronting H.G. Wells and demanding the key, the hands point to 8:50, the ensuing chase to the museum and demise of the Ripper may have used up a half hour or so, yet the time on the wall clock indicates that it is midnight.
Suggested correction: Movie time and real time don't match, so 3 hours has passed without all 3 hours being shown. The fact that the clock now shows midnight is meant to explain this fact without the need for subtitles to reveal the time.
Plot hole: Mrs. Stevens (H.G. Wells' housekeeper) witnessed HG leaving in the time machine. From her point of view (POV) it disappeared right in front of her. Yet the sign at the museum says that the time machine never worked, despite a witness that it did. (00:19:47 - 00:24:14)