...tired Science Fiction fare. The evil doppelganger idea has been done to death countless times, and Space 1999 provides no new slant.
(Richard Houldsworth, TV Zone, 1993)
There is a nothing like a good performance and in Seed Of Destruction Martin Landau's work is nothing like a good performance. What an opportunity for Landau to shine, to highlight different aspects of Koenig's personality... An opportunity that is squandered from start to finish. That old ham William Shatner does a much better job in the Star Trek episode Mirror, Mirror- the evil Koenig simply shouts at everybody and frowns a lot. The only redeeming feature of this story is that it is not a two parter. 4/10
(Anthony McKay, DWB, 1994)
An excellent performance from Martin Landau and some nice visuals in the Kalthon Hall of Mirrors lift an otherwise fairly average episode. B+
(Chris Bentley, SFX 20, 1996)
Works well because John Goldsmith's script carries the episode beyond the hackneyed premise to explore the characters' reactions to this pretender in their midst.
(John Kenneth Muir, Exploring Space: 1999, p129)
This episode is beautifully filmed, and the crystal cavern set is a very impressive example of unique and high quality production design. John Goldsmith clearly has a firm grasp on the fundamental aspects of all the Alpha characters. Undoubtedly a classic episode of Space 1999. 9/10
(Bob Wood, The Future Is Fantastic, 2001)