Davros's chair has been noticeably upgraded since his last appearance in 1979's Destiny Of The Daleks, even though he had been cryogenically frozen in the years between the two stories.
Whilst up to this point in Dr. Who, portrayal of the British Army (& it's troops seconded to UNIT) had been accurately armed, the soldiers here have a Steyr AUG assault rifle amongst their L1A1 rifles and Browning pistols - a weapon never used by regular or special British forces .
The studio technician operating Davros' lab's sliding door can be seen silhouetted behind the semi-transparent wall. When the door closes, he straightens up and leaves.
Many of the laser beam visual effects were accidentally left out of post-production (but the sound effects were put in). As such, the lights in many of the actor's prop-guns are visible when they pull the triggers (these lights are used to sync the laser effects in post-production).
The boom mic shadow can be seen when the Doctor is trying to stabilize the Tardis.