This may be my favourite George Lucas film, I absolutely love it. It's a low-budget film that looks a helluva lo better than it probably should.
The Blu-ray picture and sound are really good, and are clearly an improvement over the Dvd.
Some don't like the updates made to some of the effects, but I felt they fit perfectly, apart from one brief shot of a small creature climbing on a wall nearer the end of the film.
The extras are the same as the Dvd and are really good if you're into the film, and are interested in Zoestrope Studios.
Don't buy it if you're hoping it'll be anything like Star Wars, because it isn't. It's more arty than any other George Lucas film. I wish he'd done more like it. Sadly, I can't see that happening now.
I'd highly recommend it if you like Cult 70's Sci-Fi or low-budget films.