These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Acceptable Targets: A major story arc has Max beating up "The Diamonds," a group of Plutonian-worshipping white supremacists.
Historical In-Joke: Despite Neo-Nazis' worship of Adolf Hitler, most of them are poor, and often of what the Nazis would refer to as inferior genetic stock. Just as Hitler wouldn't have spared a decent portion of his worshipers, neither would the Plutonian have spared the Diamonds.
Alternative Character Interpretation: Oh boy. Both Plutonian and Max are complex enough to give us several different takes on them, and to some extent they all might be true. Other popular subjects are Survivor, Qubit, Modeus, Hornet, Jailbait and Alana.
Big Lipped Alligator Moment: One occurs late through Irredeemable. When Plutonian is sent to Gehnom, his unconscious body is recovered by a group of aliens that take him inside a building, and they robe him. Then they start humping his body immediately afterward. This is immediately lampshaded by someone who sees it over surveillance footage - "Okay, this just got really weird." The aliens are then called off by security, and this is never mentioned again.
Complete Monster: The Plutonian, after his Face-Heel Turn, seems to be determined to be the biggest one of these he can be. The essential purpose of the book is to ask the question of "What would happen if Superman suddenly turned evil?" Given how the first thing we see him do is murdering a mother and her baby, and that's not even the first thing he's done to cross the Moral Event Horizon, the answer seems to be "He'd fit in this trope pretty nicely, actually." The aforementioned atrocity obviously being just a beginning, he also partially and painfully lobotomized his former teen sidekick, knowing full well that he is effectively immortal and will have to suffer eternal brain damage. He later allows his former compatriots to choose only ten out of millions of Singaporeans to rescue from a massive tsunami (that he triggers, natch) prior to his absolute destruction of Singapore - which he destroyed because the UN representative of the aforementioned country wasn't entirely honest about why his country wanted to elect him as their absolute monarch. After being captured by the Vespa, he is shown to dream of reversing all the horrible things he did - implication being not because he was punished, but out of regret. Except, subsequently, when given the opportunity to redeem himself i.e accepting the telepathic alien's offer to help him, he mercilessly refuses it. As a first thing he does upon returning to Earth, he carves his initials into the USA, uses the new paradigm as projectiles, arranges a kinky threesome with Cutter and Belle Noir, and promises rivers of blood to his followers. Burrows, the man who made a town commit suicide, chooses to kill himself rather than face the Plutonian's plans for earth, and his former Complete MonsterArch-Enemy Max Damage does a complete Heel-Face Turn after being in one of the towns he destroyed.
For an extra touch of Fridge Horror, the reason Tony knows the Singapore ambassador is lying is because he hears his heart speed up when saying it, similar to real world polygraph analysis. Also similar to how real world polygraph analysis works, this can be meaningless in a high stress environment — even had the ambassador been honest, seeing a new side of the Plutonian and having his unfocused attention would have yielded similar results.
Foe Yay: Deconstructed. Modeus both hated the Plutonian and loved him, leading to him building robotic sex dolls and trying to destroy everything that might be competition, among other things.
Possibly inverted in issue #23. During his mental fugue, Plutonian sees Alana, his ex-girlfriend, turning into Modeus. Too early to say for sure but there are strong indications that Plutonian on some level wants to be loved, even by Modeus.
The first thing we see the Plutonian do is incinerate a mother and baby — and that's not even the first atrocity he's committed. He shows no sign of slowing down.
Max Damage, in the spin-off comic Incorruptible, is doing his best to be a hero despite the fact that he passed his Moral Event Horizon years ago and never looked back until now.
Even then, Max was about to cross the line by unleashing a supervirus that may have killed even him when the Plutonian showed up. Max thought the Plutonian was there to stop him before the Plutonian killed everyone in sight.
Chronologically, Tony likely passed the Moral Event Horizon when he destroyed Sky City and lobotomized Samsara.
The Survivor started inching toward it since his brother's death, and upon Tony's return was willing to murder his other brother in order to become even stronger and have enough power to kill Tony. This could be taken as a Shoot the Dog, but given the Survivor's sizable ego, and the fact that his main claim on personal suffering was Tony killing his family, that rings a tad hollow.
After capturing the invulnerable, godlike Plutonian in a straightjacket cloned from his own skin and trapping him in a Lotus-Eater Machine, what do the Vespa do with him...? They release him to use as an asteroid miner.
Gilgamos killing Survivor due to thinking that it'd give his brother all of his power; unfortunately, Survivor was the source of the power, meaning that the last sibling is powerless. He probably wouldn't have done it had he known, but inadvertently killing one of the planet's only hope left lands him this entry.