Ha ha! Yes, Gantz has a heavy fanservice influence. You'll also notice that every female featured has a minimum C cup as well.

I think the general concept of the Gantz is very interesting, I am not surprised the manga is popular. And the design of the monsters in this movie is crazy and really good, these rolling giant heads are the stuff of the nightmares. I liked more the bizarre design of the smaller monsters than the generic design of the big ones and the boss.

However, these are the only things that are good in this movie. The rest was irritating and very annoying. For example, the complete incompetence of multiple characters was just a bad choice. In the anime based on the manga I would expect more from the long legged females in the tight leather suits than just running away helplessly. Also, the way the characters were always stopping others from doing something is very annoying. Their constant talk of staying safe, not intervening, that it's too dangerous, that it's better to hide and wait, that they have no chance, was all very annoying. This is not how you tell a story, it's unnecessary to use such lines so many times in so many situations. Every time there is a chance to develop a character, to take him further to the action and discover his abilities, first reaction from everyone is "no, don't go, it's too dangerous, you have no chance". This is just dumb writing, I really hated that. The dialogs are dumb, the characters are mostly stupid, the movie is below average but entertaining enough.