This one is a bit of a mess and poorly regarded for a reason.

From sloppy child actors to equally egregiously written adults, this episode is kind of firing on all cylinders with regards to where Moffat and this era of Who can get annoying. The nonsensical plots, the Danny drill sergeant, the meandering character work - it's all a bit of a recipe for disaster. Danny in particular is so bad here. It almost makes me think the Doctor is right to dismiss him as a soldier, because he seems to project so much of his own crap onto everyone else. It does not hold up well at all.

The tree stuff is just awful. There's Doctor Who sometimes suspending credulity here and there, they basically do that in every story, but this is way too far to be acceptable as a story for anyone but the very young. Moffat ought to have avoided forests as a setting for his story because they seem to break his interest in telling something coherent.

Not to mention this episode's pretty troubled relationship to mental health, which I'm hardly okay with just brushing aside like a minor quibble. It's an outright harmful message.

Sure, there's enough earmarks of quality here and there and attempts at interesting material to keep this from going full Chibnall, but only just barely so.