Review for all 4 parts:
This story from writer Kit Pedler is historic and thankfully the quality matches its importance. And important it really is because the idea of changing the actor playing the Doctor by having him 'regenerate' into a different version of the same character was incredible and untested. It is hard now to imagine how radical this idea was at the time. If it had failed Doctor Who would have been finished whereas as the time of writing we have just celebrated an amazing 50 years of Doctor Who with the show and most of its key elements still continuing as strongly as ever.
As a springboard for all that we have this excellent adventure which also has the historic first ever appearance by the Cybermen. I really like these prototype Cybermen and even their 'sing-song' voices. I think the concept behind them is great and the story itself has them involved in an exciting attempt to destroy humanity. Their unfeeling nature and the scares and action set them up as an iconic 'monster' to rival the Daleks.
All aspects of the production are very good indeed and any flaws are minor. The story unfortunately has the Doctor sidelined a lot of the time which was unnecessary and sad in Hartnell's last regular appearance. However, when he does get involved he is as good as ever, delivering his lines with his usual charisma and that magical touch Hartnell had for being somewhat other worldly and dangerous but also endearing and delightful.
This is a classic which all fans must see. All 4 episodes 10/10.
Average rating for all William Hartnell episodes 8.26/10.