The nature of people made of anti-matter in this Season 2 episode and how they can and can't co-exist with the Alphans, etc., varies considerably from the portrayal of the person made of anti-matter in the Season 1 episode A Matter of Life and Death. (Having the aliens originating in an alternate dimension instead of involving anti-matter would've been more plausible.)
Maya calls Antares a constellation (it is one star in the constellation Scorpio). (Note: According to the script, Maya's report named the constellation as "Pintarus" - the moon is no longer within the Milky Way galaxy; furthermore, it's odd that Maya uses the term "constellation" to begin with, as it is not a true group of stars, but a perceived grouping seen from a particular point in space, such as an inclusion of a planet's celestial sphere).
When Shermeen enters the Equipment Room for a new miniature nuclear generator for Vindrus, she tries twice to touch the opening controls without actually looking at them, but can't make it. Even so, the doors open.
In the opening scene, Eddie Collins is sulking because Shermeen is paying more attention to Tony in his beer-making efforts.
When they leave with their beer, Eddie is seen sitting at his desk wearing a light jacket, when moments before he did not have one on.
The fake head of Thaed wobbles considerably at times during the performance of the actor inside (Terry Richards).
During Maya's transformation scene when the Alphans are attempting to gain entry into the temple, the face of a stuffed fox is superimposed over Maya's eye. A dog was used for most of the subsequent scene; only one shot of an actual fox was used for the outside scene.
Despite Shermeen and Eddie Collins being stationed within the Hydroponics Department, which implies vegetation being grown in water, everything in sight has been planted in soil.
The Alphans have just picked up the planet with their sensors and it's somehow already close enough to immediately send down a landing party (as well as sensors acquiring information that normally requires a reconnaissance ship to pick up).
When the original landing party disembarks, both Fraser and Koenig feel as if they'd been touched by a ghost. This indicates that they'd come into physical contact with the planet's antimatter inhabitants. This should've had disastrous effects.
When Shermeen is originally left out of the landing party, she whines that she's collected plant samples from every place they've been to. First off, some of the planets were shown to visibly lack vegetation (Death's Other Dominion (1975), Guardian of Piri (1975), One Moment of Humanity (1976)); more obvious is the fact that Shermeen has never been seen on the show before.