Gantz:O is a CGI adaptation of a manga that was an extremely enjoyable piece of work. The CGI was consistent and beautiful, the fight scenes were amazing, and the makers stayed true to the storyline to an extent, which is excellent as well. The gore was something that I had worried about since this movie is PG12, but it was very vivid for a PG12 rated film, and personally it was satisfying enough for me.
There are some changes to the characters and storyline which were a little disappointing, but to be honest those changes were understandable, and it didn't ruin the experience at all. Some of the big changes that came to my attention was,
1. The absence of several Tokyo and Osaka team members, including some members who had amazing battle scenes in the manga.
2. Katou's stance in the arc; in the original, he has already experienced battles against aliens, but in this movie he's shown to be a newbie, oblivious to the rules and weapons of Gantz.
3. An altertative ending to the Oni alien arc and Osaka arc.
Overall these changes are understandable because this movie is obviously for newcomers as well as fans, and if they had put all the characters in a 96 minute movie Gantz:O would've become a extremely rushed movie. Despite having these restrictions, the changes managed to fit in very smooth with the entire atmosphere of the Osaka arc, which is one of the reasons I give this movie such a high rating.
In conclusion Gantz:O is a film that you simply need to watch if you're a fan of the original work, and even if you aren't, it's worth the watch with a solid story, outstanding graphics and fluid fight scenes.
Basically, if you don't know anything about Gantz, I'd say don't bother. The movie clearly tries to introduce newcomers to the Gantz game concept but does so in such an awkward and incomplete way that I'd say it's very hard to understand unless you're at least kind of familiar with the rules.
The story makes some drastic changes from the manga, which by themselves wouldn't make it bad, but together make the Osaka Arc a much simpler and more boring experience (You can feel this in particular during the first half of the movie). The new ending is the only change I think affected the movie positively. Without spoilers, I'd say that while it wouldn't have had sense in the manga, it makes a perfect fit for the narrative flow of the movie.
I think the most disappointing part of the film was the music. The trailer had this really strong theme going on, but it was absent from the movie except from the credits, and all the music was pretty much the same "dramatic eleventh hour track".
Anyway, I personally enjoyed the movie, but upon thinking about it for a while, I realized it had some very weak points. I wouldn't recommend this to anyone who's never heard of Gantz, but if you want to see the Nurarihyon fight animated, or at the very least have seen some of Gantz and liked it, I say go for it.read more