Captain Proton is fraught with Flash Gordon references. Dr Chaotica largely appears to be a Ming the Merciless expy, right down to the castle and its defenses. Proton's rocket ship also has clear Flash Gordon influences. Satan's Robot is the "Republic Robot", an overused prop in various Republic serials including ''Mysterious Doctor Satan''. Finally, Proton's leather jacket with jetpack controls are the same as those used by Commando Cody/The Rocketman.
The end of "Deadlock" has a subtle one to Star Trek III: The Search for Spock: a Vidiian boarding party reaches the duplicate Voyager's bridge only to be greeted by the last seconds of a self-destruct countdown.
What Could Have Been: Ronald D. Moore, one of the patron saints of Star Trek, worked on 1 1/2 episodes of Voyager after Deep Space Nine ended. There was a well publicized clash between him and Brannon Braga over what the appropriate "mood" Voyager should be, such that he left (although they smoothed things over much later on). He did say that if Voyager was up to him, the show would have frequently been like the fan favorite episode "Year of Hell." Many of his suggestions for Voyager were later incorporated into Battlestar Galactica.
At the end of season three, either Harry Kim or Kes was slated to be killed off to make room for new character Seven Of Nine. Neither were killed off in the season finale, but the more likely candidate, Harry Kim, was seriously injured so that he could die in the fourth season premiere. Between seasons, Garret Wang ended up listed on Entertainment Weekly's list of 100 Hottest Celebrities, and the Executives mandated that he had to stay — so they wrote out Kes instead.
"Non Sequitur" was originally supposed to feature Counselor Troi as the one grilling Harry Kim in the alternate timeline instead of yet another random Admiral. The creators were unable to get Marina Sirtis on short notice. (She did appear with Reg Barclay a few seasons later.)
