This is a pretty run of the mill 'war is bad and don't murder people' episode. It's not unenjoyable but I expect it to float out of my memory without much impact in a few days.

It's a busy episode, with many new side characters, which doesn't help on top of the three-companion team, and the plot wants to be more complex than it really is. As I say, I didn't not enjoy it, but I didn't find it overly engaging - the idea of a secret alien species being scapegoated as world destroyers is... interesting, especially when they're supposed to be completely peaceful.

Part one and two did okay by Turlough, and really this whole episode, and indeed this stretch of Fifth Doctor episodes is about Nyssa, so she was treated well by the story, but neither Five nor Tegan get a whole lot to do which was a shame to me.

tl;dr, it was okay. Nothing bad, but nothing special.