I've seen about 80% of the episodes of this series in a fairly chronological order. Season 2 is definitely a nose-dive in quality from season 1 but has some redeeming qualities to it.<br /><br />My main complaint with season 1 is that the aliens are often very poorly realized - mostly just people with some slight make-up on. The only episode with an imaginative extraterrestrial on it - Dragon's Domain - is good but the monster (looking like the baddie from Luigi Cozzi's CONTAMINATION) is cheesy and immobile. The best things about the first season is the A) excellent guest stars including Gianni Garko, Orso Maria Guerrini, Giancarlo Prete, Christopher Lee, Peter Cushing, Joan Collins, Judy Geeson, etc. and B) a few never-been-seen-before science fiction ideas.<br /><br />The second season tossed these two redeemers in favor of more formulaic stories and more action and humor. Granted the humor is terrible, and the departure of Paul, Victor, and Kono unfortunate (Victor was a good cerebral anchor to the show), and the scripts often trashy, but the show remained unpredictable. The alien design got a little better especially in the episode "Rules of Luton' and the chicken-man alien costume must have been reused or rehashed for THE ICE PIRATES. Maya the shape-shifting alien, though well acted by Catherine Schell, is a terrible idea (good on paper, not on screen), with makeup different in every episode and then the tendency to transform only into Earth animals. How boring. The other regulars are good except Barbara Bain, who is not a good actress, nor is she particularly pleasant to look at. Her nostrils on her nose are pointed and bizarre looking, and at 40 she had not aged well at all, looking about 2 decades older.<br /><br />The worst episode is easily 'Missing Link' from season one, and 'The Taybor' and 'The Mark of Archanon' from season two. Just brain-dead episodes in every way.<br /><br />The special effects, while dodgy at times, are good for the era, fresh (not the same three shots over and over like Battlestar Galactica), and with numerous explosions involving fatalities. The show continuity is a bit iffy with the base suddenly having surface defenses in some episodes and lacking them in others, etc.<br /><br />All in all a fun show to watch, I just wish the quality were more consistent (like Doctor Who or Star Trek).