Better on DVD: The monthly installments come out looking essentially like sketches; spit, polish, background art, and easier-to-make-out gunfights are included in the tankoubon releases.
Complete Monster: Angelika Einstürzen specialized in human experimentation, starting on her test subjects when they're young children. Chronologically, the first thing we see her do is tell Heine, a member of one test group, that if he took part in an extremely dangerous experiment, he'd save all of his friends from the same fate. Once it was clear that the experiment was a success, she no longer needed the rest of the test group and had them go berserk and murder each other, while she forced Heine to watch. Next, she sends a large number of her old test subjects to invade the Underground City and slaughter as many people as they could before she blew her soldiers up. She didn't even do this because she had something against the people she had killed. She just wanted to get rid of her old, defective test subjects, while also getting the attention of the mayor, who resided on the surface. She figured the easiest way to kill two birds with one stone was to blow her men up and take hundreds, if not thousands of innocent civilians with them. Afterwards, she sends one of her many bodies to one of the districts hit hardest by her attack and tells the people there that their friends and family, who had been kidnapped long ago, were among the attackers that the people had killed, just to see how horrified they would be. She also shocked one of a pair of young twin sisters who understandably didn't want to go back to her for more brainwashing and Mind Rape. She does all all of this either for scientific research or just for fun.
Fan-Preferred Couple: Heine and Naoto, although if things keep going in the direction they have been, they'll become not so much fan-preferred as they will be official.
Heine and Badou definitely have a screwball couple dynamic. Particularly, Heine has a fear of women because of abuse in the past. When Naoto throws a sudden, suspicious (and hilarious) look after hearing this for the first time (we were all thinking it), Badou goes on record saying: "I'll say this only once: it's not like that." (Riiight, Badou. That totally did not induce a reaction opposite to what you expected from the Yaoi Fangirls... At all.) To be fair to them, they're both obviously straight and even have separate Love Interests, but when has that ever stopped shippers.
Giovanni has an unhealthy obsession with Heine that can get pretty suggestive at times.
Jerkass Woobie: Despite his several Pet the Dog moments, Heine's still a huge prick, but even as you feel the need to call him out on his behavior, you can't help but feel sorry for him because of all the shit he's been through.
As of recent chapters, Giovanni as well, especially since, for all his gripes, Heine managed to escape Einstürzen. Giovanni, on the other hand, never did.