I just finally finished playing this lauded and expansive game and it's leaving me vexed. While inelegant, I think some binary distinctions are a useful analytical technique here. Spoilers because, c'mon, June 2012.
Batman is both dickish and unwaveringly heroic
There are certain times in this game where Batman just comes off as dismissive and uncaring rather than merely stoic.
He was about to choose Talia over thousands of people.
For saving his life (as the game describes the act) Catwoman gets a "I broke a nail" joke
The "death" of Ras al Ghul felt like Batman just kinda said "fuck it, fall on this thing" to me
While never "killing" a thug, moves like breaking their arms and legs seem more cruel than typical batman non-murder
The whole thing with ungagging and gagging Harley Quinn is weird.
In the DLC, he's a dick to Robin
There is no player choice here. Batman will not take eternal life, will not kill a villain, will not let joker die. In major decisions, he does not waver in doing the selfless thing. Alfred and Barbara even comment on it, giving him tons of shit for wanting to save Gotham before he saves himself (if not Talia, which is weird)
All the villains are aware of and mock Batman for his unwavering selflessness. It's a theme
The game is both self-aware goofy and dark/gritty/somber/hurtful
Random thugs that you hear as you sneak up or as you move about the complex will talk about how weird this universe is. They say things like "it's hard work being a henchman" or " 'man I can't wait to fight Batman again.' 'Why? He broke three bones last time you fought him.' " The writing and voice acting are actively deconstructing the universe and the gameyness of random thugs wandering around. These hardened criminals sometimes sound more like social critics or philosophers
Joker and Riddler, despite being sadistic maniacs, still make a lot of puns (just as they did in the Animated Series). Penguin has a giant shark in the silliest "challenge" in the game. Solomon Grundy is like a Mario boss.
That (Spoilers) Clayface finale is a wacky way to end a game.
Those same thugs use the infamous bitch word a lot, talk about torturing and killing innocents, and generally come off as the largest collection of sociopaths ever
Some villains are cruel and completely unsympathetic. Penguin's menagerie is something out of Bioshock, more horror than comic book. Two Face just comes off as a prick. Zsazs is icky as always. Joker and Hugo are the best parts of the game, if only for the humanism Hugo reveals in his interviews.
The detective mode clue finding is more CSI than Sherlock Holmes.
Dude (Spoilers!) Joker dies. Of disease and doubt in Batman's kindness. He fucking dies. Hugo Strange dies. Talia dies. They do not fuck around.
The Gameplay is both rhythmic and deep and dull and repetitive
Rhythmic and Deep
I can't knock the basic flowing combat. It's responsive, it's fun, it fits the character. I got through it without being nearly as skilled as many, and I like that I can bushleague my way through something that can be done with far more grace and poise.
The movement cycle through the city glide-hook-glide-dive-glide stuff is great.
Dull and Repetitive
Like Arkham Asylum, the crux of the game is in combat zones that try to have Deus Ex style variability (vents, hanging bits, enemies of different types), but for some reason feel really same-y and cookie cutter pretty quickly.
On normal at least, the only time I felt challenged was in the battle with Mr. Freeze and the battle with Joker, the latter because of those cheap, annoying trains, but the former because you have to find four different ways to damage him, and that was great fun. That rising tide didn't really lift all boats, though.
It's not that I don't think these elements can work together to create a coherent, moving piece. The pencil scene in The Dark Knight is both horrible and funny; it leaves the audience chuckling at a man getting a pencil shoved through his face, and soon after leaves us worried that we laughed. It makes us participate in Joker's sadism.
But Arkham city feels more like a hodgepodge of tone and theme than a beautiful combination. It has a cool wrapping story of two outcasts, one chaos, one control, who need each other, in a way, to be whole. But it also has Batman going inside Clayface like a God of War battle and convicts who are alternately philosophers and misogynists. A serial killer tasks you with point-to-point races across the city. The great "test of the demon" is a glide-dive tutorial.
In trying to be serious and gritty while commenting on its own peccadilloes, the game limits the effectiveness of both aspects of its tone. I was left feeling miffed at how such a potentially powerful ending could be so colored by a schizophrenic build up.