When the Refusian enters the landing pod, it is in much better condition, and is much cleaner, than when the Doctor's party had left it moments before - the door mechanism also appears to be working much better.
When the Doctor and Dodo land on the planet, there is a visible vertical join in the backdrop.
The actors playing the Monoids have rather limited vision, as demonstrated when Ralph Carrigan, playing Monoid 2, jarringly misses the step on entering the Refusian city.
Despite being dead, the first victim of the Monoid heat gun can still be seen breathing quite heavily.
When Monoid 2 wrestles with Yendom, he shoots the human with the heat ray gun. However. Yendom is already motionless, dead on the ground before either the shot or the scream sound effect happens.
(3:17) Two 1966 BBC studio techs stand and move to exit at the left of shot behind the Doctor at the very back of the set.