1)Another interesting commentary track on this, with Davison, Fielding and Sutton, joined by Eric Saward, who manages to restrain himself and only blames JNT for stuff five or six times. (One does wonder how different these commentaries would be if JNT was still alive to defend himself.)They seem to have a general consensus that this was not the best-written script they ever saw.
2)Much is made of Concorde in this, which must have been a big deal at the time, but now when I look at it, I keep thinking what an odd-looking plane it is. Also, the tires seem awfully small for a bigt jet aircraft. And they appear to have just left one in the Jurassic!
3)When we first see the TARDIS hovering at Heathrow, the runwya is pretty obviously a still photo.
4)It's a nice twist that now that Tegan doesn't want to go to Heathrow, that's the first place the Doctor brings her. And we fnally actually get to see her being a stewardess.
5)I wonder if "perceptual induction" is what RTD was thinking of when he came up with the perception filter years later.
6)As for "Kalid" and "Leon Ny Taiy", oh, dear. Gosh, his chanting gets irritating real fast. And the question ariseth: Why did the Master disguise himself in the first place? Was it just on the off chance that the Doctor might show up, and the Master could get in a "Hah! Bet you didn't know it was me, did ya?" moment? Furthermore, why did he stay "in character" when no one else is around? Is there a "Method" in his madness?
7)The Plasmatons are fairly goofy
8)Nigel Stock does OK as Professor Hayter, the stock "academic type who thinks he knows everyhing".
9)I gather that JNT brought Waterhouse back for one last episode so that people who read ahead in the TV listings wouldn't figure out that "Earthshock" was his last story.
10)The two-headed snake puppet was also fairly goofy.
11)Davison and company make much of the fact that one of the passengers they rescue vaguely resembles Dick Cheney, implying that he is in league with the Master.
12)Some fun quotes:
More than a bit creaky, story-wise, it might've been serviceable with a bit of re-writing. Also, the whole "Gee, isn't Concorde cool?" routine hasn't aged well.
[Part of list of Doctor Who episodes here.]