This one is easily one of my favorites of the Hartnell era. Kinda a paradox, since this was the slow beginning of the end of the pure historical (in some ways).
Watching this after The Chase probably also helped it at my first viewing, since while I do find some aspect of that Story appealing, I feel like this one balances the Comedy and the stakes a lot more.

Butterworth is the great standout here really, his Monk is just amazing, and it’s a great shame we only got him here (and later in the DMP). The Monk while in many ways similar to the Master, feels to me like a unique version of an antagonist, since he really all does it to mess with it.
Another Thing I highly can praise is the Pacing, dare I say while I love the slower pace of the Hartnell era a lot, this one feels perfectly paced with its 4 Parts.
There is a lot I can praise. For example the whole subplot where Vicki tries to convince Steven that the Tardis is a time machine, it doesn’t play for too long to become annoying, no the right amount of time.
As always, Hartnell is a blast, especially his banter with Steven in the beginning is lovely “and there is a chair with a panda sitting on”