Continuity mistake: When the guy is in the mountains he burns some of the triffids at the fence and you can clearly see them frying. But when the camera pans across the garden later, there are still triffids, but they are all fire-free and there are no bodies.
Audio problem: After Roxy, Tom, and Robert discover Eegah's footprint, Robert can be heard saying, "Watch out for snakes!" however his mouth does not move at all. (00:10:30)
Continuity mistake: Mary gets out of her car at the gas station wearing white shoes, but when she is being shown her room at the boarding house by Mrs Thomas she is wearing black shoes. This also happens at other times during the film, where Mary's shoes change from white to black and vice-versa.
Revealing mistake: When the blonde stripper slaps the brunette slapper, for calling her "leftovers," in the closeup of the brunette being slapped, the hand is that of a male; very rough and hairy, and not the blonde stripper's.
Continuity mistake: Jane always pulls into her garage forward rear of car facing out. However, whenever Jane is seen pulling out of garage front of car is facing out.
Continuity mistake: Sakurai is having a steak dinner at home; in the close-up of the two steaks and fries, one of the men is holding a beer glass with their right hand, but it's not the case in the next shot. (00:07:40)
Continuity mistake: As Harry stands at the side of the traffic-filled back road, shots of panicked people fleeing down the two lane highway are used to convey the desperation of folks' attempts to flee the coast, except the shots used show four lanes of an eight-lane freeway.