Yeah I didn't have very high expectations either but then it proceeded to rock my socks off! Steven Moffatt is rather genius-like.

When you said "saved all the guinea pig people in New Earth", my first thought was weren't they cats? closely followed by maybe there were guinea pig people as well as cats, how did I miss that? and dragging along behind, finally, oh, not *literal* guinea pig people - right! It's too early for my brain.