There is a lot of trivia connected to Spearhead from Space but it is not at all a trivial episode. It was the first serial of the seventh season. The first to star Jon Pertwee as the Doctor and Caroline John as his companion Dr. Liz Shaw. It was also the first Who to be shot in color. That last bit combined with the fact that a strike caused the series to be shot entirely on film (usually at least part of an episode would be shot on cheaper-looking video) makes this the first Classic Doctor Who to be released on Blu-ray. None of this means the serial is any good of course, but it's kind of fun to note anyways.
After having his regeneration forced by the Time Lords in the sixth season finale and being forced into exile on Earth, the show begins with the Doctor collapsing outside his TARDIS. He is taken to hospital where various doctors are confounded by his strange physiology (a bit more trivia - this is the first episode in which it is noted that the Doctor has two hearts.)
Nearby a swarm of meteorites have fallen on the countryside. Brigadier Lethbridge-Stewart of UNIT (this is also the episode where he becomes a regular cast member) investigates along with Dr. Shaw. The meteorites turn out to be power units for the Nestene Consciousness who have taken over a plastics factory and are manufacturing an army of Autons (yep, its their first appearance too) to take over the world.
The Doctor spends nearly the first half of the series mostly unconscious (with periodic moments of flailing about and hilariously trying to find his shoes.) Once he awakens, he tries to run away in the TARDIS only to find the Time Lords haven erased the part of his memory that allows him to fly it. He then investigates the meteorite situation, determines the Nestene Consciousness plot, befriends Dr. Shaw, refriends the Brigadier, and destroys the Autons with an ingenious device (oh, and he wrestles an incredibly fake-looking octopus alien thing.)
There is a great deal of set-up in this series which slows the pacing a bit in the first half. They have to establish the new Doctor, lay out why he's stuck on Earth (and he'll remain that way for a few years) and firmly set-up the new companions. This causes the Auton plot-line to be rather underdeveloped and things don't really get exciting until the final act, but overall it is still a really enjoyable serial.
Between the sixth and the seventh seasons, the producers of the show knew they needed to make some changes. Ratings had been down and shows like Star Trek and The Avengers proved that science fiction and adventure stories could be enjoyed by broader and bigger adult audiences. With Patrick Troughton leaving as the Second Doctor, they decided to wipe the slate clean and go for a more mature, more serious show. Pertwee's background is in comedy which on paper makes him an odd choice for The Doctor when they are trying to take a more dramatic turn in the series, but he proved to be the perfect Doctor. He's able to provide comic relief and wonderfully lighter moments during the more serious scenes. He is regularly placed near the top of lists about the best Doctors.
This was my second time experiencing Pertwee as The Doctor. The first was in The Three Doctors where he played next to the First and Second Doctors and his on-screen time was necessarily limited. So this was the first time I got to really see him shine. And shine he does. From the moment we see him tumbling out of the TARDIS in the first scene, I was delighted with him. Even though he spends the first episode essentially asleep, he brought forth a new kind of Doctor with expert mumbling and brilliant comic timing during bursts of consciousness. Once he's awake and on the go, he fully encompasses the character. His Doctor is funny and goofy but whip-smart and deadly serious when he needs to be. Already he's turning out to be one of my favorites and I'm looking forward to watching more of his episodes.
Spearhead From Space is a great introduction to Pertwee's Doctor and his companions. Though the beginning is necessarily a bit too expository, it's well done and lots of fun. The Autons likewise are not fleshed out very well but they will get their day in later episodes (including "Rose" the very first episode of the new series.) All in all, this is a very enjoyable set.
The Blu-ray looks really good. This is probably the best looking Classic Doctor Who I've seen. There are just a few visible moments of deterioration, but nothing dreadful. One of the extras takes a look at the clean-up process and they play various scenes in split screen showing comaprisons between the original print; the original DVD print; the special edition DVD release, which was reviewed by Greg Barbrick; and the Blu-ray. The Blu-ray looks remarkably better then the original print and you can definitely tell the difference between the last DVD release and this, but I'm not sure its such a drastic difference to warrant an additional purchase. If you do not have a DVD copy, then certainly the Blu-ray is the way to go, but if you do have it on DVD, then I can't really recommend the upgrade.
Other extras include two light-hearted documentaries on Pertwee and Caroline John, plus a 22-minute segment on the opening titles. Filming the show in color caused them to have to entirely redo the psychedelic titles. The feature is essentially a set of short video clips of Pertwee standing perfectly still interspersed with various attempts at creating the groovy background.
[Cinema Sentries is currently holding a contest to win Spearhead From Space on Blu-ray. Find out how to enter.]