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.
According to the book, Ellen didn't mutilate herself just to make Viola suffer For the Evulz, she needed to inflict absolute despair upon Viola so that sorcerous immortality would fail her, otherwise Viola would have undoubtedly sought revenge against Ellen using her own magic. She still sure as hell doesn't show any remorse for it, though.
Crowning Music of Awesome: This game's soundtrack is amazingly fitting for the game's creepy atmosphere, but the theme "Miller House" is one that really pulls a Tear Jerker on you in the True Ending.
Draco in Leather Pants: A lot of fans have a tendency to paint Ellen as someone whose completely innocent, and instead shifting the blame onto either her parents, or the cat demon, or both. While it's easy to argue that her parents were partially responsible for it, the cat demon however, is a different story; despite being vague and cryptic, the demon didn't really do anything to Ellen except made offers of magic power in exchange for souls, and Ellen willingly accepted the offers. While the book goes into more detail in attempt to make readers feel sorry for her, it also shows her having early signs of sociopathic behavior, before and after she met the demon, such as not flinching nor showing any signs of guilt or regret for murdering hundreds of people, announcing herself to be Above Good and Evil, being maniacally selfish in her end goals, and finally reveling in sadistic glee at Viola's suffering; all of this was her doing, not something of demonic influence.
Driven to Suicide: Can be interpreted as this. If you return to the garden after getting the purple doll head and go to the room on the right, you'll see that the red grasses hanging from the ceiling. Though they may or may not have been attempting suicide, as other clues in the room seem to indicate the house may have done it.
Moral Event Horizon: Many players consider Ellen's backstory tragic enough that they'll excuse her having the demon eat her parents, but sacrificing innocent children to it is Jumping Off the Slippery Slope, and she crosses the line by stealing Viola's body - leaving her in Ellen's own mangled corpse - and having her murdered by her father.
Nightmare Fuel: This is to be expected in a horror game. There are numerous gruesome deaths ending in Game Overs (decapitation by giant spider, killed in revenge by tadpoles that are angry you fed their father to a snake).
The witch's glowing red eye sockets when she catches you.
Paranoia Fuel: The sheer amount of things that pursue you can do this. One off sound or sight will put you on edge. Especially when it gets quiet.
Player Punch: Viola finds a cute frog, but has to feed it to a giant snake to proceed, and its ghost appears just before leaving the room. Later, she meets its tadpoles, who accuse her of murdering their father. And just before entering the witch's room, she finds the corpse of the black cat that's been accompanying her through the house. Both endings show it alive, although the pseudo-third ending reveals it was a demon. There's also the true ending.
Made even ten times sadder by this, imagine that it was you who allowed a so called "friend" to borrow your body just because you felt sorry for her, and then you chase your "friend" trying to get your body back, only to be shot by your dad, YOUR OWN DAD!
The Woobie: Viola. The poor girl is tricked into trading her body with a 'friend'. Said 'friend' cuts off her legs and gouges her eyes out, simply because she wanted to make her suffer before dying; she then force-feeds her a throat-burning drug because she doesn't like the sound of her old body screaming. Viola is then shot to death by her beloved father, and the witch laughs at her corpse.