Visible crew/equipment: Near the beginning when the men are hauling the equipment to their camp, you can see a crew members hand in the bush literally toss the fake giant spider on top of the passing equipment. (00:13:10)
Revealing mistake: When Jerry Manley gets bitten by the spider in the tent in South America, the others come to look at his corpse, you can see clearly see his neck pulsating, when he should be dead. (00:15:35)
Visible crew/equipment: When the dog and the cat run out through the dog flap, you can see the puppeteer moving behind the flap handling the spider. (00:18:55)
Audio problem: When Bunny says "Yo Dr Death" when riding off in the car with Shelley, her lips don't move. (00:58:05)
Continuity mistake: When Becky is in the shower, the position of her hair as she washes it changes, and the amount of shampoo bubbles in her hair differs also. (01:09:10)
Revealing mistake: When Becky gets out of the shower naked, her father walks in on her and you can clearly see her wearing pants, reflected in the mirror, to keep her modesty. (01:10:05)
Revealing mistake: When Becky sees the spider in the shower, there are two instances when you can see the bodystocking she's wearing, covering her breasts, to preserve her modesty, most noticeable when she screams. (01:11:53)
Other mistake: When Dr Atherton injects the mouse with venom, the syringe is pointing up. But as the plunger is pulled nearly all the way back and the syringe is too large to be filled with venom, he would have injected the mouse with air. (01:17:00)
Revealing mistake: When the scientists inject the mouse with poison, they put it in a jar. The, after they place it down you can see someone's hand swap the jar for one containing a dead mouse. You can even hear it. (01:17:58)
Continuity mistake: When Irv and Blaire are snuggled up on the couch, watching Wheel of Fortune, watch the big bowl of buttery popcorn they have. In the first shot it is full to the brim. In the next shot it's half full. (01:18:15)
Revealing mistake: In the scene where Dr. Ross Jennings is trapped in the corner of the cellar, you can see that the tarantula which starts climbing up his leg has a huge black stick stuck to the back of its body, pushing it along. (01:36:05)
Visible crew/equipment: When the explorer goes up into the loft to find the king spider, he taps the fake web string, says 'suppers ready" and then the fake spider dramatically shoots out from a tech wire 'screaming", and attacks him. (01:49:24 - 01:49:50)
Continuity mistake: When the General jumps out of the flames, one of his legs breaks off after he hits the ground. All eight legs are intact after he is blasted by the nail gun and crashes into his nest.
Factual error: Jerry Manley's corpse wouldn't have been returned to his home town as depicted. He died in a foreign country outside the U.S. from what was thought to have been a fever, his corpse would have been quarantined for possible contamination and autopsied which would have quickly determined his real cause of death from the spider.
Factual error: The spider being fried by the fuse box simply can't happen. Fuses are insulated for that very reason.
Continuity mistake: When they perform the autopsy on the three victims, Metcalf is all grey and stiff, whereas the two exhumed victims look alive and fresh.
Other mistake: Irv and Blaire's death scene doesn't make sense. When Irv poured butter on the popcorn, he should've noticed the spider in the bowl. Also, when Blaire picked the spider up, she should've felt it. Both of them still appeared to be watching the TV after being bitten, which also didn't make sense. Why didn't they have seizures like the other victims?
Continuity mistake: Near the beginning, the clumsy guy walks backwards into a giant cobweb, so he is covered in it, but, as he leaves, there isn't a cobweb in sight on him.
Audio problem: Right after the doctor falls in the basement he is talking about how no spiders are going to be there. Then he keeps repeating "Oh s***" but it looks like his lips are delayed.
Revealing mistake: When the flaming "general" spider is killed, there's several mistakes. When it leaps, it suddenly "freezes" in mid-air for a second before the nail hits it. Then, when we see the nail hit it, you can see a wire attached to it, plain as day, to yank it back. Then, when it hits the egg-sack, you can see several fake spiders attached to it, which don't move at all. Then the egg sack catches on fire, but the flames come from behind the sack, even though the general hit the front.
Suggested correction: Not that what you said is wrong, but it actually makes sense. Metcalf was bitten by the original, non-bred spider. The other victims were bitten by spiders that were part house spider, part deadly spider. Therefore, the effects of the bites were different. I'm quite glad that I only had to see one gray, shriveled-up body.
Actually all three were bitten by hybrids.