I'll be honest, I enjoyed this book but the last hour really kinda lost me. It just felt they threw everything at it. The inclusion of the 9th Doctor throughout multiple hours was great, but the 2nd Doctor one felt shoehorned and rushed, and unnecessary. Nice tie-in to the S6B BF stuff though! The Slitheen plot twist is spoiled by the cover, stupidly, and also happens very late in the game. I think the characterisation of Doom here is great, it really does sound like Sooz when you read the dialogue. The choice to make the hours interconnect was great, it really elevated the plot. Again though, I did feel it lost its way at the end.