I'd like to give this episode a 0/5 for it has derivative ideas, illogical plot points, Martha acts like a dope, and her mother acts like a biatch. But for some reason, I just like it and want to give it a 4/5 but I guess I can settle on 3/5. The reason I guess is that it has some of the best action scenes, a sense of urgency, and some arresting visuals. And the illogical bits could be explained, I guess. I don't know why the heat creature couldn't just jettison the fuel itself, it certainly has the chance to rather than attacking everyone but perhaps it just couldn't really function in our world that well. The music is fine, especially the version of the promo music that has that sense of urgency and desperation. The story turns into a "GET" Doctor story which some fans will note as a part of fandom that likes their heroes to suffer and here, the Doc suffers more than ever. Tennant again does a great job throughout although Freema drops the ball a few times and that could be because of the direction. Chris Chibnall, who I believe created or was highly involved with both the excellent mystery/horror/supernatural show STRANGE (which also had Tom Baker as a guest star and possible regular for the 2nd season that never came about) that should have stayed on (although if a web site that told what would happen in season two was truthful, then maybe not) AND the equally excellent SEA OF SOULS (which has in the last episode of season 3 Paul McGann who could have been a semi regular mysterous sorcerer who might have been an ally in the season 4 that never happened although we did get a two part movie that was highly strange). Anyway Chris did great, IF I'm correct that he was involved with those...much better than this off kilter script and the awful stuff he did in TORCHWOOD.
I digress. The "get" Doctor factor, the Martha and hot boy Riley (with yet another gay reference....was he gay or bi?) stuck in the jettisoned Pod, the visuals, the music and the action all kind of make me like this story when all logic says that I should not. For the script has a lot wrong with it. See THIRD DIMENSION book for all the stuff that is like an Opps! and just doesn't make sense. A thing they didn't catch was that the plot is like from an old SPACE ACADEMY (Yeah I liked that show and still do in a way) about a living star. I'm sure that story is even older than that, dating back to the 1950s sci fi and maybe earlier than that. The other thing is that the creature could have told the crew what it was doing rather than just killing them off one by one (cliche time). There's more but I won't go on and on about the faults.
The cast: some say that this was miscast. I disagree and can totally believe that all of these actors are the characters they play. They're pretty good in all cases, actually. Michelle Collins, I don't know her from I think EASTENDERS but I saw her in eps 2 and 3 (or rather story two) of season one of SEA OF SOULS, I believe as a mother who has a reincarnated son who wants revenge...even if he is like 5 years old! She was great there and is great here. The cast who play the crew are equally good.
So there you have it: good music, good effects and visuals, a great effort from Tennant, Martha even recovers from her dopeyness, and it's a shock, really, that her mum has joined up with what looks like a future enemy of the Doctor or even an enemy group. She's that far removed from Jackie. The human aspect of the love of the husband and wife and Martha's family and Riley looking for something in someone remains a high point of the story and the script. Martha telling the Doctor, "Turns out we didn't need you in the end" is a stupid comment as he saved her and Riley and got infected that way. Glad to see the Doc vulnerable here.