Much better than last week. Very 'Alien' in places, hunting something nasty through a confined space, but Doctor Who has 'borrowed' ideas from other sources before. The redesign of the Ice Warrior looks even better on screen than in still pictures.
Good performances all round, good music (and not intrusive this week). Skaldak's face when seen was decent CGI, though not entirely convincing. The exterior shots of the sub were excellent.