The manga Gantz is terrible on a variety of levels (“mature” in the most juvenile ways possible, overly photo referenced, slow production), but I can’t help enjoying it’s gusto and the biggest weakness – the fact that Hiroya Oku is clearly just making shit up as he goes along – is also its biggest strength once it gets past the Buddhist Temple mission, introduces Shion Izumi and the wheels fall off any semblance of sanity in the story.
So of course we don’t get any of that in the anime, and instead GONZO make up their own ending. That’s not helped any by Ichiro Itano’s leaden direction, meaning what should have been one of the greatest action shows of the decade is a worthless mess.