Parasyte/YMMV

Bittersweet Ending - The Parasites' organization is broken, Goto is dead & the Parasite race is apparently on the decline, but it's come at a heavy price. Because of all the school he missed fighting the Parasites, Shinichi can't get into college, tantamount to a death sentence in modern Japan & thus his future with Satomi is uncertain at best. Migi has put himself into an induced coma for reasons known only to him, Shaba is going senile & it's implied that with the Parasites fading away, humanity will eventually render Earth completely uninhabitable.
Complete Monster - Kabuto.
High Octane Nightmare Fuel - So much...
HSQ - Parasyte could easily be renamed to "HSQ: The Manga".
Narm - When Shinichi is at death's door, Migi fills the roles of trauma surgeon, nurse, AND organ donor in order to save his life. It should have been the dramatic turning point of the story in more ways than one, but thanks to the visuals that accompany this scene... not so much.
Squick: see Fan Disservice in the main page.
Ugly Cute: Migi when in 'talking' form.
Uncanny Valley - In the story, Parasites generally are indistinguishable from normal humans. However, they tend to have completely blank expressions due to not having emotions, and the artwork often gives them slightly overlarge and sharply-defined eyes that give them a sinister appearance. Extremely twisted humans, such as Kabuto and Takeshi Hirokawa, also have these eyes. There's also Sanji.