Easily the best episode of the season so far and the best Doctor Who script ever written by Mark Gatiss. The drama is well paced and backed by an amazing supporting cast. The redesigned monster looks menacing while still being true to the original design from the classic series. Really, the only flaw with this episode is that it feels a bit rushed.
It is 1983. A Russian submarine is returning home with an rock-music loving professor and his recent find - a frozen figure he believes to be a mammoth. But the truth is far stranger and the TARDIS materializes on-board the sinking sub as The Doctor quickly recognizes what the scientist has truly found - a cryogenically frozen Martian! Introducing himself as Grand Marshal Skaldak, it seems the Ice Warrior has been trapped in the ice for over 5000 years. Displeased by this revelation, Skaldak's shock becomes rage after he is attacked by the fearful soldiers of the submarine's crew. Now it's up to the Doctor to stop Skaldak from arming the submarine's nuclear missiles and triggering World War III in retaliation for the assault on his person.
THE GOOD PARTS
* Mark Gatiss' script is brilliant, perfectly capturing the feeling of a classic Third-Doctor era Doctor Who episode. The Ice Warriors were used surprisingly little in the classic series which I personally found to be a shame as The Ice Warriors have one of the most memorable developments out of all the alien races on the show. They started out as your typical would-be alien conquerors but later evolved into a no less dangerous but far more peaceful race. Indeed, The Doctor was forced to confront his own prejudices regarding The Ice Warriors and what they were versus what they had become in The Curse of Peladon and we see a lot of references to that episode here, with The Doctor talking about how the Martians were presumed dead but they are merely scattered and will one day rebuild their empire.
* The re-designed Ice Warrior costume looks amazing, both with helmet and without. I always felt the classic Ice Warriors had one of the best designs in the classic series and the new look resembles their old costumes well enough while still looking far more high-budget.
* This episode is aided by an amazing supporting cast. The highly-underrated David Warner's excellent performance as the Duran Duran-loving Professor Grisenko is a real treat. Likewise, Tobias Menzies (Brutus on HBO's Rome) is suitably treacherous as the cowardly Lieutenant Stepashin and Liam Cunningham (Davos on HBO's Game of Thrones) is perfectly cast as the submarine Captain. Skaldak himself requires the combined efforts of two talented actors, with Spencer Wilding as the Ice Warrior's imposing physical form and actor Nicholas Briggs providing Skaldak's sibilant speech.
* Matt Smith is in top form. He doesn't get any big speeches this time, but it is nice seeing him play against type. Usually The Doctor gives the alien menage a speech about how awesome humanity is and why they deserve to be spared. Here, he appeals to Skaldak's sense of honor, basically arguing that humanity isn't worth the trouble. It's an interesting twist on the usual theme.
* Your enjoyment of this episode may be dependent upon your tolerance for certain classic Doctor Who tropes, particularly the aliens being less monstrous than they appear and the cliche that the soldiers always make things worse by presuming everything is a threat as The Doctor and the other scientist characters plea for peace, talking problems out and using your brain before using a gun.
* A frequent problem with many classic Doctor Who stories is that they were overly padded and went on too long. This episode suffers from the opposite problem. Between Professor Grisenko and his talks with Clara, the subplot with the lieutenant trying to curry favor with The Ice Warrior to strike a blow against his American enemies and The Doctor's negotiations with both sides over giving peace a chance, this is one of the few New Who episodes that might have benefited from a second episode to let the characters play a while longer.
* Clara seems awfully dismissive of the power of music, given her experiences last week in The Rings of Akhenaten.
THE FINAL VERDICT
My opinion may be biased as a long-time fan of the Ice Warriors, but I loved this episode the best of any thus far in Series 7. The script is fast-paced - perhaps a little too fast paced given all the various stories playing out at once. Still, the supporting cast is wonderful and Mark Gatiss' script true to the original concept and portrayal of The Ice Warriors. Hopefully we won't have to wait another 38 years for their next appearance.