"Winged Assassin" is the first episode of "Captain Scarlet" to feature contributions from uncredited voice actor Neil McCallum, who also voiced guest characters in the episodes "Big Ben Strikes Again", "Codename Europa" and "Expo 2068". The episode also marks the first appearance of the series' secondary title sequence, in which the Mysterons transmit their latest threat to Spectrum while the green Mysteron "eyes" (or "rings") slide menacingly over members of the regular puppet cast. These shots were recorded during the filming of "Winged Assassin". The episode's incidental music – a suite running to 4 minutes and 38 seconds – was recorded by series composer Barry Gray in a four-hour studio session on 3 April 1967.