The villain,- pretending he is God, makes a stun gun vanish from Koenig's hand and appear in his own. But due to sloppy editing, a stagehand can actually be seen placing the gun in the villain's hand where it is supposed to suddenly appear.
While firing at the giant lizards, one shot lacks a beam from Tony's laser as he's firing (an obvious flub from the Opticals department). Some disc versions have corrected this.
Similar to The Full Circle (1975), a large pit is excavated without the use of digging tools. And in both cases, there is no evidence of soil deposits in the area (and in this case, the Alphans themselves aren't even dirty).
As Koenig is lowered into the pit (which was constructed on a raised set) to test its effectiveness, the commlock falls off Martin Landau's belt and is heard landing on the studio floor.
Koenig kills one of the ape creatures right near their camp, but the body is never seen again after that, implying that the Alphans just ignored it, lacking interest in observing an alien species.
The first time Alan attempts to launch his Eagle, he states it has been 24 hours since their missing party had left Alpha. However, it seems that only a short time has passed for the Alphans on the planet; in fact, it's nighttime where they are, after arriving in daylight just before sunset.
During the Alphans' first night on the planet, they encounter several aliens near their camp that have run off. In total darkness and with no visible sources of light, not only do they find footprints of the aliens, but they're able to follow them.
By the time Koenig sends Maya out on a reconnaissance as an owl, it has already been established several times that Maya and Tony can't touch each other. Yet after Maya transforms into an owl, Tony holds her on his arm. If the interdiction doesn't work while she's in a form other than her own, the Alphans should take note of it, and if it does still work, then Tony shouldn't be able to hold her.