This prologue of Fate/stay night: Unlimited Blade Works doesn't really deserve to be it's own separate release. It's still as enjoyable as you would expect however. Because this is only a single 'episode', I will try to keep this review concise. The story is basically trying to be a somewhat short introduction to Unlimited Blade Works, and it does it's job just fine. It's nothing outstanding, but the story itself is enjoyable in it's own right. The animation and sound are, again, incredibly impressive and they really carry this anime and all of it's different iterations to entirely different degree of 'epicness'. It improves the enjoyment by aton.
Overall you will obviously enjoy this if you like any of the other Fate iterations, or if you want to watch some excellent action combined with one of the best, if not the best, animations and a stunning soundtrack.