(spoilers) Yes. I think the violence is done tastefully by showing the brutality that comes with war, and the brutal gore of it all is an important part to the central theme of Gantz, but then rape is just kind of treated like a joke. Their is literally a character who just rapes the aliens, and then that's it. That's like his whole thing. There's no good commentary or messages behind the fanservice, and the author just seems like a pervert. The manga literally opens in every chapter with random half naked girls, some who aren't even in the fudging plot at all. Reika basically creates a Kei as her lover, forcing him into a position where submission to her is his only option, which then kind of just forces them together (argueably SA). The dog scene kind of solidified it for me early on that the author is just a weirdo creep. Honestly made me really dissapointed.