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.
YMMV: Light and Dark The Adventures of Dark Yagami
Ass Pull: the Life Note, each special ability of the Royal Death Note, Naomi's true identity... Dark's magic cellphone is both a metaphorical and literal asspull.
Although the Life Note is fairly common in Death Note fanfiction and appeared in the manga pilot in the form of a Life Eraser.
The Everything Note enables Dark to become king of the world, destroy all "nuclears," and go back in time.
"HE HAS A DARN EVERYTHING NOTE! THAT TIT IS TAKING THE PISS NOW!"
Night has skin made out of Death Notes. She can get tattoos to kill people, and at one point her skin appears to be Everything Note as she can pose as a guy naked by writing 'I'm a dude' on her skin.
A Teleport Note enables Hal Linder (who is inexplicably male in this version) to teleport into Dark's house.
A Ghost Note enables L to come back as a ghost... even though ghosts don't "exits".
The Pain Note in the spinoff series lets Raye put anyone in pain. The Sick Note appears to do the same thing too. Neither one actually advances the plot once the author has exacted his insane "revenge" on canon characters. Both are just lying on the floor when needed. Ditto Near's Blind Note.
The Talk To Dead Dudes Note and the even more utterly unhinged Talk To Not Dead Dudes Note which mysteriously just float up from the bottom of the sea.
The Anti-Life Note is then Asspulled out to Retcon the previous Asspulls. Except it apparently doesn't work.
In what must be the one of the oddest Asspulls ever, Creepy Dude gets a Secret Death Note, which can't be detected by "Death Note radars"... from a volcano God.
Hell, the very existence of a "Death Note radar" is an Ass Pull.
There are "Sex Notes". What they do is unclear, but they seem to give TIOSEFAJ blonde hair and a killer rack. In the epilogue, it's mentioned Samanther/ Light's Mom has a sex note but it's not a Note, merely a book where she's written down people she wants to have sex with. Dark/ Soichiro being the only name on it so far.
The Shield Note saves people written down from the nuclear bomb that destroys the world. Yet there are some characters who inexplicably survive without the use of one, so it's effectiveness may be in doubt.
In another of the author's stories, L meets a Shinigami called Secks who gives him her 'Time Note', which presumably lets someone travel in time.
Canon Defilement: most of it. L randomly getting a Life Note is particularly bad, though.
The author admits that he changed Naomi from being Japanese to being British because it would make the story cooler.
Cargo Ship: "She locked at near. 'You just thinked about making a laddie out of lego and sexing it.'"
Crazy Awesome: Blud's description in chapter 13, just read it: "Standing over him snarling and dropping bits of blood and slobber was a fierce dude with twenty feet tall. His blood mowhawk was blooder than ever and there were dead peeps stuck to the spikes screaming in pain. His tooths had been sharpened so they were all sharp and bumpy like a saw and strong enough to chomp bone or concrete or even diamond but he didnt eat them cos they were pricy. He was wearing a coat of armer made of lava with guns and swords and cannons stuck to it. He was driving a motorbike and it was powered by nuclears which made it faster." Plus the 17 crossbows, stuck together with blood and "duck tape"!
Every last page, word, punctuation mark, and space in this story positively exudes this trope. Never before has this much insane awesomeness been seen in one location.
Les Yay: Sayu/Misa, Takada/"Desk Lady", Naomi/Night.
Mary Sue: Dark Yagami: Somewhere between Villain Sue and Jerk Sue; and Night Yagami, whose skin is made out of death notes and who has Shinigami eyes and ears. She's also prophesied to "sign" the song that ends the world.