Ass Pull: Santa's sleigh magically warps back to the North Pole at the end. Not only is it right out of nowhere, it contradicts an earlier scene where Santa says he can't just fly back home on an airplane because "what would I do with my sleigh?"
Nightmare Fuel: We see what's clearly the actor actually narrowly missing running over a dog in the street.
Kevin: Oh thank god. This is the kind of movie that would actually kill a dog!
Padding: Dear God, yes. Thumbelina takes up 61 of the film's 95 minutes of run time, and if you took that out plus all the unnecessary long shots in the Santa scenes, the whole thing would be roughly five minutes long.
Questionable Casting: Near the end, Santa gets too hot and decides to take off his coat. Hilariously, the guy playing him (Jay Clark) is pretty skinny, and only looks to be about 30 or so.
Retroactive Recognition: Kim Nicholas (the blonde head elf in the opening scene, then she shows up later to toss a frisbee and bring a donkey to Santa) went on to a major role in Impulse, a.k.a. "That cheesy low budget thriller William Shatner made in Florida when his career was in the toilet where he plays a sociopathicBluebeard."
The "gorilla" brought in to try and help Santa is clearly just a man in a cheap gorilla suit.
The biggest example might be Santa's "stuck" sleigh. You can clearly see the thing moving in several scenes after "failed" attempts to extract it. Also, it appears to be "buried" in a quarter-inch of sand. In certain spots along the rails. Which Santa almost entirely cleared off in a few seconds before giving up. (It probably would've helped if Santa got out of the damned thing when they pushed.)
The ending shot of Santa's sleigh disappearing is accomplished via an obvious in-camera edit where they stopped rolling the camera, physically removed the sleigh from the shot, and then started rolling the camera again. Noticeably, the children stop excitedly milling around the sleigh and stand perfectly still in preparation for the edit — and it's clear that they couldn't hold still enough for the amount of time required for the sleigh to be removed, as several of them suddenly shift position when the sleigh vanishes.
Squick: When Santa gets out of his sleigh to help with the sheep, you can see a huge dark stain on the back of his pants. Please God, let that just be sweat!
More than likely, they painted the sleigh too close to filming time and so all that black paint rubbed off on the Santa suit over the course of filming, given that Santa is seated for about 80% of the film and he's outside in the humid heat near the shore, which would also cause the paint to rub off.
Stock Footage Failure: The movie uses some stock footage of reindeer on a grassy tundra... in a scene that's supposed to take place at the North Pole.
The various animal costumes. The costume design was so poor that several of the animals look like the fever dreams of a mental patient. The RiffTrax guys point this out by screaming in what can only be described as mortal terror.
The shots of the rides at Pirates World, which naturally include a bunch of kids, really spell out how far amusement park safety standards have come since the '70s, and can seriously make you wonder if you're about to see some horrible accident.
Awesome Music: Perhaps the only thing about the whole movie that comes close to being described as awesome (or even tolerable) is the Happily Ever Aftersong, at least compared with everything else. However...
Ending Fatigue: ... it goes on forever. Doesn't help with the long framing device final sequence when the girl meets her boyfriend at the park after seeing the diorama.
Mis-blamed: While some people have criticized the movie for completely dropping Thumbelina's mother from the story after the first act, this is actually faithful to what happened in the original story — it was Don Bluth's animated adaptation that gave her mother a more prominent role and had them briefly reunite at the end. That being said, the lengthy sequence with the witch has the unintended side-effect of increasing the mother's role in the story, making it all the more jarring when she's suddenly dropped.
The costumes of the various animals. In particular, the "stag beetle" costumes have their mandibles mounted vertically instead of horizontally, making them look more like parrots (which might be what the costumes started out as, seeing how the film was produced in partnership with a pirate-themed park).
The set designs, which look more like blown up versions of grade school dioramas. Which, to be fair, is what they're supposed to be.
They had trouble getting proportions right, either the coffee mug Thumbelina is standing next to is miniscule, or the walnut shell she sleeps in is gigantic (maybe both).
One scene in particular has Thumbelina looking at a scratchy, faded rear projection of her mother as she talks to Thumbelina, intending to be a shot from Thumbelina's perspective. Instead, it comes off as both this trope and Nightmare Fuel. One blogger notes that it looks like a scene from Nineteen Eighty-Four.
When Thumbelina and Mr. Bird are shown flying, the sky is just a plain white background (with obvious shadows on the walls), with a fan offscreen blowing gently in front of them to further simulate the "effect" of flying.
Speaking of Mr. Bird, in the scene where he's standing next to Thumbelina, the costume was obviously very front-heavy, as it nearly tips over a couple times.
The Spinster had Thumbelina created since she was too old to have a daughter of her own. One day, Thumbelina is kidnapped by a frog, and while we never see the Spinster again, she's completely devastated.
Thumbelina herself is pretty woobieish. She's kidnapped by a frog, is tormented by some bug... things after she escapes, and is then almost forced into an Arranged Marriage with Mr. Digger. Fortunately, she eventually gets free and gets to be queen of the flower people.
The Jack and the Beanstalk adaptation contains examples of:
Awesome Music: Compared to the Thumbelina segment, the songs in this one are actually pretty decent at the very least. If anything the singers are much better too.
The "golden hen" is pretty much just a store-bought ham wrapped in gold-painted newspaper.
Also, the magic harp, which was built with "eleven cents in three minutes" according to RiffTrax.
All of the props in the giants' home are inexplicably scaled far too big from them. This makes it seem like they are small instead of huge, or else are renting from bigger giants.
The bad rear projection appears again, but only briefly compared to Thumbelina.
Squick: In one scene with Honest John, one of his potential customers is sporting a very visible, very prominent male cameltoe!
Unintentional Period Piece: All the characters except Honest John and the giants wear contemporary (1970) clothing that's very much of its time. One suspects it's because they had to use the actors' own clothes.
blog speculates that, rather than the real Santa, the movie is about a Florida eccentric who thinks he's Santa Claus. Maybe the non-stop Mind Screw moments are just his heat stroke-induced hallucinations.