I'm afraid I'm going to have to go against fan consensus here as I didn't really enjoy this one that much. It was by no means terrible but it wasn't amazing either. I was expecting the sort-of-satanist themes to be what would put me off, which I still wasn't a fan of, but it was actually that the story was just really quite boring. Not much happens and it didn't do anything for me. I don't have anything against simplistic plots because they do work, but this one felt too simple.
Personally, no one got any great, outstanding and memorable scenes in this story except the Brig. I wanted to enjoy this one because I'd heard a lot of good things about it, but unfortunately this story didn't deliver for me and I'm disappointed. I'd have liked to have seen more of Bok and Azal, and see them actually do more, too. Bok just runs around a couple of times, whilst Azal is out of frame for most of his scenes. They had potential to be cool villains but I think they were missed opportunities here. Azal's defeat was a bit of a cop-out and unimaginative, too.
My favourite bits were with the Brigadier, such as with the spectacled UNIT guy and the machine, the 'five rounds rapid' line and, as Ronpur mentioned, his last line was awesome! It was also nice to see Yates and Benton a bit more involved, but even then they still don't have much to do.
It wasn't an awful story at all and it had a few merits, but it was mostly just a bit 'meh' and disappointing for me.
2 stars, I think.