When the plant in the aluminum can germinates, its stalk reaches above the top of the can. In the next scene, the astronauts remove the plant to examine it and put it back inside; the plant, stalk and all, is shorter than the can.
When Lieutenant Howard removes a space barnacle from the incubator, its uppermost petal is erect. Howard sets the space barnacle down, and in the next shot the petal is drooping.
Major Benedict's suit backpack is different, when he exits the crashed spacecraft, than what it was in the remainder of his scenes.
The narrator's reference to the NASA's Mercury Project is accompanied by footage of a German V-2 rocket being launched. He also says that Mercury was the first manned space programme. It was the first US manned space programme - but Vostok by the Soviets was the very first by anyone.
The rabbit that was supposedly killed by the plant in the space station was seen to be still breathing.
The strings that open the petals of the space flowers are plainly visible.
Captain Doweling reports to Earth that Major Benedict is unconscious while Benedict is sitting upright and moving.
It is said the alien plants can penetrate metal. This is never seen, even though they are discovered growing in a car engine.
Col. MacWilliams decides in favor of four men (one already dead) over the lives of every living animal on Earth, and then decides to withhold information from those going into first contact with a deadly alien life form. This is decision-making at its worst.
In his only dialogue scene, Lieutenant Howard refers to Captain Doweling as "Major Doweling."
After repeated warnings that the crew of the spacecraft was facing a deadly space virus in the form of plants, the rescue party (including top NASA brass) comes across the crashed spacecraft wearing no protective gear whatsoever.