Disclaimer: My Review for this and 'The Satan Pit' are the same, simply because my Opinion on both Episodes are very much the same.

Oh, finally the first “Masterpiece” for the Tennant Era, honestly it’s been a while since I watched it, but I can’t think much of the issues I have (besides the lovey-dovey of 10Rose, but the Story is so good, I don’t really care much about their banter). Having Woolf return to voice the Beast was just a clever Choice, his Voice fits the role so well and while the Beast with its effects aged a bit poor, I still find it quite impressive and especially ambitious. The Soundtrack is great and well the Story does so much right!
Suspense? Yes there is!
Great Designs? The Oods are probably one if not nuwho’s best alien design we got, so good!
And a great side cast? Definitely, which can be quite rare for NuWho
Dare I say, this also has one of the very great Cliffhanger of NuWho!