Quite a well-written, fun, interesting story having The Doctor be holed up on an alien world for 600 years with a new companion and a new lease on life, almost being a different incarnation all together and this is all explored decently well with also having a nice, fun, well-functioning plot. Good stuff!
Sadly, however, the story hasn't aged terribly well with it having The Eight Doctor's Adventures' second instance of outright transphobia; having the main villain be a trans woman whom everyone treats as ridiculous for claiming to be a woman, misgendering her constantly, having her be a take on the transgender/crossdressing serial killer trope and using outdated terminology, like, "Used to be a man", which all seems double-y offensive seeing as Paul McGann is openly very supportive of trans folk.
So trans folk out there, stay away if you're not in an exceptionally good place right now, however, if you are in an exceptionally good place right now (go you!) like I am (I'm also trans, not just bragging) you can enjoy this, and just roll your eyes or grit your teeth at the transphobic comments as a sign of the times, the same as we do with racism in Classic Who.
7/10