Odd little aside, because I do a lot of research into psychology, philosophy and literary theory in my spare time, I tend to keep "safe search" switched off, otherwise I don't find a lot of the deeper thought stuff out there. When searching for the images for this post, I found a lot of images of the female characters from this film (and the broader franchise) that would be considered pornographic, or at lest erotic, in nature. Sure, I find the same when I search up anything with a broad fanbase, but the ratio here was really high, enough that I'd comment on it. It's a shame that so much focus is on women in black latex, because the bones of the concept are pretty good. Those who die untimely deaths can earn their way back to life by defending the innocent from monsters, the framing device being something akin to a video game. When players accrue enough "points", they are given three options; leave the game and return to their lives, get a more powerful weapon or revive a fallen comrade.
I may need to hunt down more of the Gantz franchise, as the bare bones mentioned above are a great concept for a role-playing campaign. Ordinary people, forced to fight aliens and monsters in an attempt to find their way back to the world of the living. I wouldn't be shocked if there was something like that out there already. Can I recommend the Gantz franchise on the back of Gantz:O? No, but I will seek out more to take a look at. I probably wouldn't jump onto this film unless you can get by on the concept and visuals alone, it creates more questions than it answers. Fights are still pretty cool though.