The amount (and position) of white in Zareta's hair changes several times.
In the duel between Kull and Taligaro at the beginning, the width of the blindfolds changes between shots.
When Juba rips off Zareta's accessories, the right shoulder strap of her dress falls down. It is back up in the next shot, then down again later.
Kull's sword changes between shots in his duel with Taligaro in the chamber of Valka.
It's clearly a stunt double under Kull's helmet for the majority of the rescue of Zareta from being burned at the stake. As Kull now suddenly is way more capable with a sword and nimble than star Kevin Sorbo, as well as being shorter.
When the King hands the crown to Kull a smoke-pot is visible in the crown to give the appearance of heat.