Rewatching this and I have found myself fast forwarding through Mark Twain. Personally I find his presence does not advance the story in a good way and his voice to me is the equivalent of “nails on a chalkboard”. I find the actor so hammy and ott he just ruins any scene. The writers could have fleshed out the story in another way, by explaining a bit more about the aliens. I know people will disagree with me, but like a lot of TNG stories, the guest stars often ham it up to a ridiculous degree. The difference between Times Arrow and one of the best TNG episodes (Inner Light) is remarkable. Inner Light is beautifully written, simple and understated.