This is basically a twist on a haunted house story. The creepy atmosphere - a big old house with a strange landlord, creaking and scuttling noises and mysterious attacks beginning to happen - works really well.
The biggest plus to this episode is the big name guest actor David Suchet putting in a wonderful performance with real depth. He is a mixture or creepy and gentle then properly scary when he gets angry but he is also very moving when he gets upset.
Peter Capaldi is on usual top form and makes so much entertainment from his humour mixed with his dark intensity.
Pearl Mackie continues her excellent performance as Bill who is a really really good companion. She is strong and full of personality without dominating or being pushy or annoying.
Bill's student friends are believable and well acted and the dialogue all round is high quality. This continues in the end scenes where Nardole makes his usual cameo and the mysterious situation that requires the Doctor and Nardole to guard a vault is built up further with the prisoner within becoming more obvious and interest in that ongoing thread growing nicely from the scene.
The direction and effects are very good and tension and atmosphere are cleverly built. The creepiness is a really great aspect of the story and the payoff is surprisingly emotional and thoughtful. The woodlice creatures are an interesting 'monster' that can be compared to the maggots in The Green Death, although the wish to include bioluminescent elements is a bit too similar to the fish from the previous episode, Thin Ice, and to creatures appearing later this series, so that is a tiny thing I would have changed with the design to avoid overuse of the same thing.
Really this brings everything I want or expect from a Doctor Who episode - a creepy situation, a threatening monster, strong dialogue, amusing humour, great acting and a decent plot. I therefore rate it very highly.
My Rating: 9.5/10.
Series 10 Episode Ranking: 4th out of 14.