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.
Base Breaker: Mink. Either he's the worst Bastard Boyfriend ever, an unredeemable piece of shit and the worst love interest for Aoba outta all his prospect boyfriends, or he's a Jerk Ass Woobie who's deeply damaged due to his Dark and Troubled Past and his more sympathetic in Re:Connect is enough to forgive his deeds, or at least understand where he came from.
Broken Base: The anime adaption, while many fans were excited to see the whole thing animated, there are some who were afraid that it's going to turn out bad just like what happened with Togainu no Chi's anime adaption. This has died down, due to the anime actually being decent with really good soundtrack to boot.
During the sequence where Aoba uses Scrap on Mizuki, letters start start to pour out of Aoba's body and appear in front of him. This freaks him out and he runs off. The letters were probably going to form a word puzzle like in Koujaku's Scrap sequence, but Aoba didn't know what he was supposed to be doing. Consequently, the player never gets a chance to solve the puzzle, and Aoba inevitably fails to save Mizuki.
When Aoba runs away from the letters, you hear the same laughter that happens when you make a mistake during Mink's Scrap sequence, although this might just be the other people in the room.
During the Rhyme fight at the end of Ren's route, the reason only Noiz's Allmate was there is because Noiz was the only one to recognize the bug and remove it from his Allmate; all the others would've been berserk.
Why is the only time Aoba bothers to use that stun gun when you're taking Ren's route?
We've seen how Mink and Kojaku's groups can get into Platinum Jail during their respective routes, so how come no one but your chosen love interest ever bothers to come in (barring Ren's route, of course), even though it's completely possible?
In almost all of the bad ends, Aoba winds up either dead or tortured, so why doesn't his evil side come out during them? Virus and Trip route I'm looking at you.
Could also be fridge horror when you realize his fate could've been so horrifying that even Desire wanted nothing to do with it.
Memetic Mutation: "iiyo" Explanation Near the end of Koujaku's route has Aoba repeatedly say "That's fine"/"iiyo". In his bad ending, he won't stop saying which causes Koujaku to scream. Fans found his scene scary yet hilarious.
"You fuck the Dog" Explanation Ren, Aoba's allmate, who takes shape as a dog, has a route and in the good ending he has sex with Aoba, in his online form. (Though some fans consider 'you fuck the dog' to be a Discredited Meme.)
To a lesser extent, it has been argued that "the dog fucks you".
"Mizuki got friendzoned." Explanation Mizuki, one of the few major characters, does not get a route as he spend the rest of the game in a deep coma. (He does have a route in RE:Connect though, but it takes place after the good endings, which at that time Aoba has a boyfriend)
Koujaku's Adorkable personality can fall into this
Narm: Many fans have pointed out when Toue says how he'd like to find a way to dramatically murder someone, it was in no way elaborated on. The thought-to-be Title Drop was so incongruous, fans have made fun of it.
All the Off Model shots in the anime, specially in episode 3.
Although, Shiki goes through a lot of character development throughout Tn C that Mink does not. Especially if you listen to the Drama CD which is in Shiki's point of view, it turns out he ad libs through much of his interactions with Akira.
It's a double standard even in the context of the game. Specifically, Mink is reviled for his rape and abuse of Aoba, but Virus and Trip not only get a pass, but are wildly popular and are many people's favorite characters. This might be because Virus and Trip are unapologetically evil and abusive (and catering to non-con related kinks without any excuses), while Mink is a Troubled Abuser and lots of players have (for very understandable reasons) problems with a trope that involves having sympathy for a character who treats his/her love interest badly, even if their Dark and Troubled Pastis a good one.