Welp, finally saw this. It didn't blow me away, but it's decent enough and doesn't do anything offensively bad. It might even be fair to call it the best video-game-to-movie adaptation ever, considering how little that means. I can't say for sure if it would make to sense to someone unfamiliar with the first game, but it just might stand on its own, though it can feel a little bit dense and muddled at times.
Something came to mind while watching the film that also struck me in watching Death Note: it felt like they had a budget for exactly this-many fancy FX shots and not a single shot more. It's not a feeling I can ever recall getting from a non-Japanese movie. Do you think this is common in Japanese films?