Some people count the Yuuichi/Makoto ship as this as Makoto is a kitsune given human form. However, everything happens while she is a human, and they do not end up together in the end; furthermore, in this adaptation, the "marriage" plot is inferred to be out of pity rather than love.
While the outright mentions from the VN are removed, a character is implied to cut and scars on her wrist are briefly shown. Mai's war against the demons turns out to be a form of self-harm once it's revealed that they are everything she rejects about herself given form and killing them injures her.
By many Western standards, Nayuki's crush on her first cousin would be incestuous. While she has a route in the VN and her feelings are treated as legitimate and unproblematic in all media, in the anime, her feelings are unrequited.
There is a scene like that in the visual novel (the protagonist tries it as a prank, he grabs the wrong head and realizes he's submerging the cat instead of his intended target, freaks out, and pulls back; the cat survives and is just fine, and the whole thing takes a few seconds). This is not included in the anime.
Every episode begins with "Dream... I'm having a dream," and describes fuzzy memories or visions of what is happening or has happened. One character's magical ability turns out to be something akin to reality manipulation.
No, but one is involved in a bad accident and is put on life support. Another character turns out to be trying to distance herself from the idea that her sister is dying.
A character falls out of a tall tree. While she doesn't actually die from the fall, merely becoming comatose, it is inferred and the audience is led to believe that the character is dead for a number of episodes.
The main character is left behind with relatives so his parents can pursue job opportunities overseas. Two other characters' situations can be construed as parental neglect until you realize the truth.
Played for laughs near the end of episode 2 -- Makoto has been following Yuuichi around the shopping centre to confront him, but her "attack" is pathetic and she injures only herself.
No, but Ayu's and Makoto's situations can be construed as parental neglect until the truth about them is revealed. Child abuse and neglect do appear in AIR and CLANNAD, which share a universe with Kanon, so be aware if you intend to watch all three.
A pet is abandoned in backstory. A cat is dropped off a bridge as a "mercy" in comparison to going home with humans who the perpetrator feels would mistreat it; the cat survives unharmed and is eventually taken in out of remorse.
A cat is dropped off a bridge, but is miraculously saved by a truck driving under at just the right time. The character who dropped the cat feels immediate remorse and goes to rescue it. In the original visual novel, the cat is later almost drowned but again escapes unscathed; this is not in the anime.
While the original VN's sex scenes were clumsily written and didn't always come off as consensual as they were meant to, these are removed entirely here. The main couple is lightly implied to still have sex offscreen once, but there is no hint of assault.
A character is shown about to harm themselves with a sharp object, but they don’t go through with it. Another character is shown to have scars from hurting themselves, but nothing more than this.
A 16-year-old, as well as a 10-year-old in a flashback, are implied to die, but turn out to survive. A girl with the body and mind of a teenager, but who is technically 7, does die but is lightly implied to be revived in the end.
In order to get around adapting multiple romance routes without cheating, one relationship ends with death and three are turned into unrequited crushes, with a mutual kiss from the VN replaced with a one-sided kiss that shocks the recipient.
One mother, in a flashback, dies in hospital but is revived. Another is gravely injured, but eventually survives. Ayu's mother is mentioned to be dead.
-The demons in Mai's arc are invisible and akin to some ghost interpretations. -A character dresses as a bedsheet ghost for an ineffectual prank. -A dead character appears before a living character as he falls unconscious. It turns out not to be a true ghost, but a living person with a strong resemblance to the dead character, and he had just imagined the dead character in his delirious state. -A main character turns out to be an ikiryou, a type of "ghost" of a living comatose person. For a few episodes, she is suspected to be a true ghost.
Mai, who is bisexual, commits suicide onscreen; however, she is able to revive at the last minute with her healing/reality-warping powers, albeit weakened, and spends most of the remainder of the series in the hospital. Sayuri, who is strongly implied to be a lesbian (and the anime removed the VN's unfortunate "she just needs the right man" subtext), is nearly killed by demons, but similarly survives her injuries.
There are quite a few episodes containing fanservice. These characters are usually minors/high schoolers so such scenes may be upsetting to certain viewers.