Gantz the movie (Part 1 & 2) is worth a watch. Originally a manga and anime series, Gantz is about two friends who are hit by an subway train and find themselves in purgatory. From then on Gantz, a large black sphere, directs their existence by setting them tasks to kill aliens. Points earned for successful missions can get them back to the real world.
The CGI effects especially in Part 1, are impressive. A spectacular scene is when an alien in the form of the thousand-armed Goddess Kwan Yin, went ballistic when attacked by the hero- a thousand swords wielding in all directions at the same time.
Part 2 was screened three weeks after Part 1 ended. A new approach to serialised movies? After watching Part 2 it was obvious why. The movie needed loose ends tied leaving Part 2 lacking any CGI magic. Be warned, it would be pointless to watch Part 2 ahead of Part 1 either.
You can read the manga for free (yes and in English too) at this website.