Just installed on Windows 10 tablet. I know its still alpha so not sure what you've not implemented yet and what you know doesn't work but here are some observations.
The preferences screen can be a bit difficult to read depending on the backdrop being displayed at the time. I think to keep it consistent with other UWP apps it should just be a plain colour background, maybe with all options on one scrollable screen, if not a tabbed screen, see Explorer for YouTube.
What is the see more text supposed to do on the home screen, it currently doesn't do anything. If it's going to get a purpose then I'm afraid it looks quite awful stuck all the over to the right on its own in blue font colour.
I think the amount of actor/crew images displayed on the movie details screen is a bit excessive. If your meta data lists a load of actors and crew it just becomes a endless scroll of circles. For those missing an image you should implement the default image from the Microsoft Film and TV app and used elsewhere by Microsoft as a default person image. I think chapter images should be included before actor images and implement a list of suggested movies. Could also do with some media info, resolution, audio channels etc. The trailers button doesn't work.
When going to the main movies page the first screen to open was resume, I had no items to resume so this page shouldn't be displayed and it should have took me to latest.
I'll leave it there for now, why I mess with TV views.