It's mostly just okay. Najia is fun (I particularly like when the Doctor tells her that she "raised an awesome human"), Graham's character moments are good, and for a straight-faced take on a creature feature, it does well enough. Only real complaints I have are 'Jack Robertson' for how basic of a caricature he is (with how prevalent piss-takes of that particular guy were between 2015 and 2020, these jokes were already old hat), and the dubious framing around the Doctor's endgame for the titular Arachnids. In an attempt to continue NuWho's pacifism and mock cultural obsessions with firearms, it ended up shooting itself in the foot and made Jack look like the reasonable one by comparison. Big yikes.

I don't even mind the Doctor being morally screwy (it's why Seventh is one of my favourites), but the blind handing-over of benefit of the doubt for that decision and the lack of self-awareness thereof doesn't sit well with me. It's not quite "Amazon is good, actually" from Kerblam!, but it's up there.