Wouldn't it have been better to have used an established character for Skeletor to create the double of, like Man-At-Arms or Teela, rather than create this Koldar guy who we know nothing about?
When the evil double of Koldar causes havoc in Grayskull, The Sorceress refuses to defend the castle against him because "It is written that Castle Grayskull must forever be a safe haven for the friends of He-Man." Er, this guy is trying to take over the castle for himself, doesn't sound much like a friend, hey?
What exactly is the deal with the 'Hall of He-Man'? If this room of Grayskull (never seen in any other episodes) is as old as the castle, it would imply He-Man must be thousands of years old!
If He-Man and Koldar really are such good friends, why does He-Man sound so suspicious of Koldar when he expresses his desire to see Grayskull?
Where exactly has this Koldar guy come from? The episode implies he's known He-Man for years, so why have we never seen him before?
Sorceress: ...for it is written that Castle Grayskull must forever be a safe haven for the friends of He-Man.