This was a very by-the-books episode. An incredibly generic base-under-siege episode with generic characters and suffers from too many nostalgia references.

It's not been long since the Doctor and Nyssa left Tegan at Heathrow and Adric's death, so this story feels remarkably empty in terms of characters, and it takes a while to get used to. Usually on Big Finish, the fifth Doctor is given a new lease of life, giving him the chance to be commanding and powerful, stealing every scene he's in - however, it's fairly early days for the company and he gets the bare minimum, the writer going so far as to just replicate his character rather than to add more layers to him. Whilst she's the focus and is a lot better here than she has been in most of the TV stories, she's still unbelievably bland. Both Peter Davison and Sarah Sutton try to show off more of their characters and bring more to the table, but when the writing isn't there, it's a struggle.

So the monster here is essentially a ripoff of the Silurians, no? Or even the Ice Warriors - animals from the Permian Period have survived and are roaming about Alaska. I wasn't a fan of the continual mentions of the dinosaur fossils from Earthshock - and if you're going to mention Earthshock, it'd be nice to get some more character development regarding the aftermath of their close friend's death, and the dinosaur itself (why are they calling it a Permian and not a dinosaur) was just a bit meh. He was just hanging about and roaring and had some magical powers for some reason? And he didn't actually do anything? It's some real terrible handling of a monster, when the entire plot revolves around it you need to do something with it otherwise the story just falls flat.

This wintry background could've given the story a very atmospheric, isolated feel but they didn't do too much with it - I like the creepy lab aesthetic, but the soundscape is very confusing and doesn't help to sell this scenery at all.

I have absolutely nothing to say about the side characters - there's a subplot where two scientists are acting like children, and it's unbelievably stupid, and instead of the Doctor and Nyssa developing as companions, the Doctor gets another companion to accompany him in the story, and her lines are very ridiculous "I rant when I'm nervous" or whatever. We got that, you don't need to spell it out for us.

The score is so bland.

This is so boring. I really struggled to listen to this because it had nothing to keep us engaged, and was a very basic episode. The actors try their best but even they can't salvage this story.