I actually don't like film adaptations of anime, there's something crazy about trying to follow a series that's roughly 12 hours in length down to a suitable movie format of 1.5 to 3 hrs. What surprised me about the film adaptation of Gantz, is how well they adapted the idea of getting transported to a room relentlessly by a alien sphere to fight aliens shortly after your own death, instead of simply trying trying to mash the plot into a shorter format. They kept most of the aliens, but changed a lot to the series which is pretty refreshing after it had been out for five years. Also, the film is just as brutal and violent as it is in the anime, maybe even more so with the film's added realism.
