What the hell did I just watch?
Massive overblown monk threat!!!! Oh no, all sorted in ten minutes by someone thinking of their mum while the Doctor shouts a meaningless 'explanation' over the top. All that setup for that?
Missy had no significant role to play and the 'Timelord with a Soul' thing is weird and a bit on the nose for a show that's normally a bit better at moral grey area. The Doctor is allowed to be morally complex, but the Master is either weeping good or cackling evil?
Standard derivative dystopia, stolen from 1984, Equilibrium, V for Vendetta, etc etc - even the First Order from TFA got a costume based nod. We only saw it all for a few minutes and never got to appreciate what live was like in this world so it's hard to care very much about them overthrowing it or feel a sense of overwhelming odds.
The fake out regeneration we all saw coming was a literal fakeout regeneration? Ok, fine. Can the doctor generate regeneration light shows at will, or was that him totally wasting it for a performance? And what was the point of the performance given that Bill had no reason to expect that to happen? Was it just so they had those shots for the trailer?
Nardole having the bacteria was entirely irrelevant to the plot, then? Why bother infecting him at all? And if the Doctor's managed to free all his guards, find nardole, hatch a plan, and dispatch him to the mainland, why exactly does he need to wait for Bill to find him before going straight back to the university that Bill came from in order to enter the vault? Why not just skip straight to that bit? He doesn't know he needs Bill to fix this until after he's spoken to Missy.
Worst episode I've seen in a long while.