A strong beginning to Twelves DWM era, he is characterised perfectly in his series 8 mold, that harsher, darker Doctor,  but still the hero. Eight and Clara are separated for basically the whole story but get a great closing scene. The art work is wonderful, capturing our Tardis Team and the Umbra look great, contrasting greatly with the environment. They are defeated in an interesting enough way, and all the side characters are memorable, Rudy Zoom makes a characterful antagonist.