It all begins here... a mysterious police box in a junkyard, a secretive old man... well, viewers didn't actually see this episode but it's interesting as a fan to watch the untransmitted pilot, if only to see how the show might have turned out had Sydney Newman not insisted changes be made. There aren't many differences between this and the broadcast version but what is different is very different, so had this opened the series in 1963 it could well have gone down a different path. We're quite happy with what we got, so this remains little more than a curiosity, its own entity in a similar vein to the Peter Cushing films.
As in the broadcast version, schoolteachers Ian Chesterton and Barbara Wright are curious about their pupil, Susan Foreman, and her strange behaviour. They decide to investigate. Having watched some TV drama recorded as live, I'm familiar with some of the tropes: flubbed lines, boom mikes in view, it's 60s television. Unlike anything else from the period, however, observations are easier because I can directly compare this episode with the revised version. Here, the school scenes are directed with an aim to create a mood of mystery and unease. Technical gaffes let down any attempt to create mood - one of Ian's lines is noticeably cut off by way of the editing. Actors William Russell and Jacqueline Hill don't seem as comfortable with each other or their lives as they will in the broadcast version, but it could well be that I'm just more accustomed to seeing the "proper" version that I resent this alternative.
Following Susan home to a junkyard, Ian and Barbara meet an old man, who they believe to be concealing Susan inside a police box. William Hartnell's performance is probably the most striking part of the pilot, certainly if you're used to his later mellowed performances. Despite almost all of the lines being the same in both versions of this episode, Hartnell gives the Doctor a sinister edge here, while in the reshoot it's obvious all along that he's harmless. Keeping in mind the only sci-fi element in the plot so far has been the mysterious vibrating police box, and a schoolgirl apparently being held captive within, one might think this is going to be a very different kind of programme.
We now get to see the inside of the TARDIS as Ian and Barbara push past the Doctor. As the Doctor talks down to the schoolteachers inside the TARDIS, it's not clear where the episode is going - the Doctor has shown none of the qualities we will come to associate with him, and it's hard to imagine ever sympathising with him. In this version of the show, Ian and Barbara are not only the heroes, the Doctor is the villain. A 1963 viewer might expect the story to end on their side. Would there have been any doubt the Doctor would bash the caveman's head in when the "original" Episode 3 comes around? He'd probably bash Ian's head too for trying to stop him. They could still all end up friends, but it would take longer to get there than it ended up taking.
There are a few errors already mentioned - scenes changing too quickly, the tripping camera operator, but nothing so serious that the episode is unbroadcastable. It's well directed, creating a grittier atmosphere than the broadcast version. It's a question of whether I prefer that approach of the more relaxed, comfortable one we got. Some things are better in this version - the gunshot in the titles is a nice touch, and some of the lines that got removed were good, but the majority of the changes were for the better - softening the Doctor's character, removing the reference to th eDoctor and Susan being from the 49th century (imagine the ramifications of keeping that line!), introducing Susan's dilemma of choosing between her grandfather and her new life in the 20th century. Sydney Newman wasn't to know the changes he insisted on were crucial, but thank goodness he did because we without them we might not still have the show today. I doubt we'd even have had it in 1970.
Scare factor - It's an episode where the Doctor is the villain! And Hartnell makes a pretty good vilain.
Funny factor - Paving the way for a humourless Doctor. No thanks.
Drama factor - Ian and Barbara's situation seems very desperate, because Susan doesn't seem to be on their side. It's heavy on exposition and very tense - this isn't the Doctor we know and love, and we don't have that reassurance that he'll do the right thing. As a what-might-have-bveen, that makes for good viewing, but I wouldn't have wanted that every week.
The pilot works well as a curiosity, but in almost all respects the broadcast version is better.