Art Shift: The art changes constantly in style, partially due to the length of time it took to make the book, partially due to J O'Barr's emotional state.
Ax-Crazy: For justified reasons, Eric is barely in touch with this reality and often pauses to recount some memory that suddenly resurfaces or to quote lyrics or verse at his victims before brutalizing them. "What the hell you talkin' 'bout, man!" is a frequent reaction.
Cats Are Mean: Sort of. After returning from the dead, Eric finds that he has a magical power over stray cats, who eerily follow him everywhere. (The cats don't actually do anything bloody or cruel, however, as Eric does.) Subverted with Gabriel in both the comic and the movie, who has white fur and is named after a Biblical angel. In the comic, Gabriel was the pet of an old woman who was murdered by Tin Tin purely For the Evulz; in the movie, he belongs to Eric and Shelly and stays in their (condemned) apartment after they're murdered. (In the movie, Gabriel does become angry and bites Skank, but that was only because the thug grabbed him.)
Darker and Edgier: In-story example. Eric, in life, was a cheerful and happy-go-lucky mechanic. Now? Not so much.
Hair of Gold: Shelly is blonde, sweet, innocent and angelic.
Humans Are Bastards: One of the more unnerving aspects of the comic are the fact that the antagonists don't rape, murder and steal for some specific goal; they mostly do it because they can, or because they feel like it.
Limited Special Collector's Ultimate Edition: A definitive "special edition" of the comic was released in 2011. It features a new foreword by O'Barr and new or previously unseen artwork that O'Barr intended to include in the original release but couldn't due to the constraints of the format, in which page numbers had to be multiples of 16. The additions include but are not limited to:
An extra page in Gideon's pawnshop, in which Eric advises young rookie cop Albrecht to reconcile with his estranged wife
A flashback sequence of Eric and Shelly dancing together
A flashback sequence called 'An August Noel' which O'Barr says was so autobiographical in nature that it was simply too painful to include it the first time around
A penultimate sequence called 'Sparklehorse', in which Eric mercy-kills the horse in the barbed wire from the earlier 'Shattered in the Head' sequence, symbolising his final acceptance of the fact he wasn't able to help Shelly and has a discussion with the crow that very explicitly lays out that he's been trapped by his anger at himself as at the gang who attacked him and Shelly that night. The sequence takes place between Eric killing T-Bird and the final sequence of Eric at Shelly's grave.
The Lost Lenore: Shelly just may be the most iconic example of this trope in comic book history.
Maybe Magic, Maybe Mundane: The "crow bringing a soul back from the land of the dead to put the wrong things right" mythology was created for the film franchise. It is never explicitly stated in the comic book what is going on. A possible interpretation of events is that Eric was actually revived on the operating table and has been subsisting for a year, and is now insane and maybe insensitive to physical pain, as a result of his brain injuries, grief and anger.
Meaningful Name: Officer Albrecht and Captain Hook, both named after members of Joy Division/New Order. Eric's last name (gleaned from a file folder with Hook's thumb obscuring the middle) begins with "c" and ends with "s"; it very well may be "Curtis".
In the foreword to the Special Edition O'Barr says that he named Eric after the Phantom of the Opera because the character, like himself at that point in his life, was a grief-stricken obsessive monstrosity barely functioning beneath a mask. Shelly was after Mary Shelley, the author of 'Frankenstein', a story in which a creator loses control of his monstrous creation.
Meaningful Chapter Name: Chapters of the comic are song titles or verses from iconic bands such as Joy Division and The Cure, among others.
Mr. Fanservice: Like you would not believe. He spends half his time shirtless and the other half in skin-tight clothes, he's got scars and troubled pasts galore, and there's even a twenty-page pin-up section.
Never Heard That One Before: The police captain has the last name "Hook" - which, yes, makes his name "Captain Hook". It's implied that Hook found this funny earlier in his career, but over time became absolutely disgusted with people constantly bringing it up.
Suicide Is Painless: Funboy accepts his unavoidable death, agrees to act as Eric's messenger boy to the rest of the thugs and talks things over fairly civilly with Eric rather than futilely trying to resist. Eric rewards him by allowing Funboy to kill himself by a massive drug overdose, sparing him the savage vengeance he inflicts on the other gang members.
Right Wing Militia Fanatics: A band of farmers connected to an anti-government militia feature as the bad guys of The Crow: Flesh and Blood. They kill federal conservation officer Iris Shaw via a bomb in the building where she worked, a blast that also claims the unborn child she was carrying. When Iris comes back, she hunts down each of them and deals with them in true retributive fashion.