Continuity mistake: Dr. F arrives at the train station and stands to the left of the candle light. A second later he is right in front of it.
Continuity mistake: During his lecture on the brain, Professor Frankenstein draws the medulla oblongata on the black-board twice. (00:05:45)
Revealing mistake: In the classroom Frederick stabs himself in the leg with a scalpel. Look closely and you can see the thick pad covering his thigh inside his trouser leg. (00:11:10)
Continuity mistake: When Dr. F meets Igor and says "You were sent by Herr Falkstein, weren't you?", the expression on Igor's face from a side view doesn't match the immediate following the front shot (smiling / serious). The rest of the shots changing back to front do match.
Continuity mistake: At the cemetery gate, Dr. F tells Igor to crouch, which he does but very slightly. In the following angle Igor's position is totally different, being crouched at ground level with his hands on a different place.
Continuity mistake: When watching the grave diggers with Igor, Dr. F's hand on Igor's shoulder swaps sides depending on the angle.
Audio problem: When Frankenstein first opens the door to the monster-making room, the rusted handle breaks into two pieces, but when he throws them down, only one piece can be heard hitting the floor. (00:28:15)
Continuity mistake: During Inspector Kemp's visit at the Frankenstein manor, Frankenstein is playing darts while he is having his conversation with Kemp. He throws the first dart at the bottom 10, but by the time he throws the second dart at 7, the first dart he threw at 10 is now at the bottom of 18. (00:56:20)
Continuity mistake: When Frankenstein releases the monster from the experiment bed, he reaches for the third bar (over the monster's thighs) first, but the fourth bar (over his lower legs) is already open. All of them were closed when they left the monster in the lab. (00:46:50 - 00:53:55)
Visible crew/equipment: After the monster catapults little Helga from the seesaw to her room and she is tucked into bed, it is possible to see the wire that was used to pull the covers up (when her parents enter the room). (01:06:25)
Continuity mistake: At the castle, Dr. Frankenstein throws darts while talking with Inspector Kemp. The shot of the darts hitting the board does not match with the shot where Inspector Kemp takes the darts back from the board. (00:58:50)
Continuity mistake: During the scene where the blind man, Gene Hackman, is serving soup to the monster, the blind man spills 2 large ladles of soup onto the monster's lap. The blind man then burns the monster by lighting his thumb, thinking it's a cigar. The monster screams, and breaks through the front door, leaving the blind man's cottage. When the monster leaves the cottage, there is no sign of the spilled soup on his clothes. (01:08:50 - 01:10:55)
Audio problem: After Dr. Frankenstein flips his last dart behind him during his dart game with Inspector Kemp, a loud commotion of breaking glass is heard, but behind them is only the castle wall and a set of fireplace tools that are undisturbed.
Revealing mistake: For most of the opera house stage presentation, the monster is a full head taller than Friedrich. During the tap dance, however, they're the same height. Although the camera angle/depth of field used tries to disguise this by keeping Gene Wilder in the foreground for most of the shots, it's still apparent that Peter Boyle isn't wearing his probably-impossible-to-dance-in platform shoes during the sequence. (01:24:00)
Continuity mistake: While playing darts at the castle, Inspector Kemp upsets Dr. Frankenstein by talking about the possibility that he has created another monster. This distracts the doctor as he is throwing his five darts (one ends up on the wall, two out the window, one hits a cat, and one is tossed behind his back). But when the inspector's car leaves, there are at least six darts in the tires. (00:59:45 - 01:01:15)
Continuity mistake: When Dr. F climbs up the hay cart, the first wide shot shows him with his waist above the cart. The next shot, from the cart's POV, shows him only shoulder level.
Continuity mistake: When Frau Bluecher is talking to the Monster for the first time, she puts her hand on his head. In a closeup shot of the Monster's face her hand and arm are missing.
Revealing mistake: Before The Monster sits all the way down on the teeter-totter that launches Helga into the air, she begins to get airborne before The Monster settles his end of the teeter-totter all the way to the ground.
Audio problem: When they first find the monster conscious, Frederick says "Is the sedative ready?" The reply, "Yes, doctor," comes from Frau Blucher, who isn't there, and doesn't make another appearance in the film until she releases the monster and he escapes. It should've been either Inga or Igor saying it.
Suggested correction: I thought it was supposed to be Inga.
Continuity mistake: When the blind man serves soup, there's a spoon in a cube on the left skewed to the right. A couple seconds later it's straight.
