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: Kelso. Everyone falls into one of two camps: either he's a total badass who was a better protagonist and more fun to play than Cole, or he's The Scrappy who derailed the last few cases of the game due to being a Marty Stu action hero in a Noir setting. There are no exceptions.
On the flip side, finding out about Cole and Elsa's affair can be a potential base breaker, either showing the former's still human or being the point he becomes unlikable.
Catharsis Factor: It feels SO fucking good to run over the sexist, racist douchebag known as Roy Earle with a car. Granted, you get a Game Over if you kill him, but it still feels SO satisfying to do it.
Dr. Harlan Fontaine, the Big Bad, is entirely behind everything. At first, he looks nice, however he manipulates Ira Hogeboom, a traumatic patient, into burning down the house of people who wouldn't sell the land, and his only objection to families being killed was that it drew bad publicity. What else is that he is willing to kill anyone who discovers his dirty secrets, even to the ones he's been nice to, such as Courtney Sheldon, who considered him a mentor and came to him for help and Elsa Litchmann, who hadn't pieced it all together.
The Black Dahlia murderer aka Garrett Mason is known for murdering women by beating to death or strangling them, then leaving their bodies naked in public places with messages carved into their skin. All while framing innocent men for his deeds and sending messages and his victims possessions to the police to taunt them that they hadn't stopped him.
Captain James Donnelly for being an Irish Catholic Bad Ass.
Fridge Horror: The public will never know about the real serial killer who murdered all those women, but at least those innocent men Phelps arrested are let loose with a few technicalities so all is right, correct? That is, until you realize that those innocents did not have their names cleared, and will always be viewed as murderers.
Specifically, the Golden Butterfly case. The public clearly wants you to charge Eli Rooney, a local pedophile, over the victim's husband despite the fact there is overwhelming evidence against the latter. Many players do indeed go against the LAPD's wishes and convict the husband, Moller. However, this unsung hero path is eventually revealed to be pretty devastating: you lose the opportunity to lock up a dangerous pedophile while ruining an innocent man's life with a permanently tarnished record.
In addition, while none of the suspects are as bad as 'The Werewolf' some are very dangerous and unstable individuals. Rooney the pedophile, MacCaffrey the man with a history of violence toward women and clearly unrepentant if pressed about it, Stuart Ackerman the violent and deranged hobo that has claimed to killed numerous women before. All people that will get released into the public again.
Elsa says Cole convinced her to fight her morphine addiction. But he died by the game's end. And the last time she had someone close to her die, in her first appearance, you could clearly see her taking morphine to deal with her grief (albeit administered by Fontaine). Cole's death could drive her back to her addiction again!
During the war, the Marines had to deal with their enemy being holed up in caves and possibly being on their backs, preventing them from just moving past them. Cole insisted on having his unit clear out caves as ordered, while Jack instead had them sealed with demolition charges. The one in seen in a flashback with Cole ordering Ira to burn it out with his flamethrower turns out to be a cave full of civilians, which undoubtedly messed up Ira upon his realization of it. That being said, Jack's lead being followed means that cave full of civilians and other soldiers dying trapped and likely no one bothering to realize they were ever there... hardly a better prospective end.
It's Easy, so It Sucks: Some have argued that the gunplay being overly simplified (compared to GTA and Red Dead Redemption) makes the shoot out scenes either this, or frustratingly unpolished. It gets really noticeable near the end of the game when things start going crazy.
Idiot Plot: The Homicide desk. Hoo boy. About half a dozen women all found dead in the exact same unusual circumstances, some with messages clearly meant to taunt the police, and it isn't until the penultimate case that anyone seriously entertains the idea that there's a serial killer. It's somewhat justified by Captain Donnelly being a borderline Knight Templar obsessed with delivering swift retribution, but it's still jarring.
However, Phelps does uncover more than enough evidence to charge the suspects, and even though he's wary of how convenient it all seems, he doesn't have the proof to say otherwise.
Magnificent Bastard: Arguably Garrett Mason; it takes five wrongly-accused men before the LAPD realizes that the killer is still out there. Not to mention that he comes face to face with Phelps and Galloway in the first Homicide case without either suspecting him.
Marty Stu: Jack Kelso. For a guy who exists to show Cole he's not perfect, Kelso seems pretty perfect himself.
Most Annoying Sound: Get an interrogation question wrong. That little bit of music is the game mocking you. But...
Most Wonderful Sound: The clunking piano music you are rewarded with for making a successful accusation, as well as the sound of your XP bar filling.
The sound that plays when you've discovered all the clues on a scene.
Narm: Fail the DLC Traffic case, "A Slip Of The Tongue". It's worth it, just to see the normally cool Captain Leary scream "DA CHIEF'S GOT MY BALLS IN A FRYING PAN!" and kick a bucket at Cole as he and Bekowsky make themselves scarce. Can be witnessed here in all its glory.
Nightmare Fuel: The entire Black Dahlia case. The entire thing is just a very unsettling matter to deal with, almost going into a horror movie type deal.
When you hear the explanation on why the corpses of the victims of an arson case look like they're praying, I betcha you'll feel something in your stomach.
From Bad to Worse: While discussing the evidence, or lack thereof, one of the corpses crumbles. It's too much for even Biggs to handle.
If you want to make it worse, after checking the corpse, listen to this piece of soundtrack YMMV though.
Ira Hogeboom: You said the house would be empty!
During the "Manifest Destiny" case in Vice, you inspect the Hollywood Post Office after finishing a shootout there...and find a wounded shooter who dies shortly after. The look in his eyes just as he dies...
Not as bad as the other examples, but Jack's scream as he's run over by the bulldozer if you don't move fast enough is pretty shudder-worthy.
The penultimate war flaskback. In the one before it, Cole sends a man, flamethrower wielding Ira Hogeboom, to clear out a cave complex suspected to be filled with Japanese. While he does it successfully, it turns out that the cave complex was being used as a makeshift hospital, with several civilians in it. The game thankfully doesn't show too many of them burning, but it certainly shows enough to get the point across. The guilt and horror of this is what ended up causing Ira to go insane, and even then he seemed to already be losing his grip on sanity, as he needs to be held down by other guys while screaming and wailing.
"He's not so bad. He just lays on top of me and grunts for a few minutes. He's kind and he buys me nice things." As said by a twelve-year-old girl, speaking of a fifty-two-year-old man.
Replacement Scrappy: Jack Kelso, who the writers seemed enamored with enough to make him pretty much subsume Cole's role in the story.
Scrappy Mechanic: Many people have taken issue with the hyper-sensitive driving controls. Regardless of whether or not it's a problem, it's a definite polar opposite to the car handling in GTA IV. Hilarious to watch, regardless.
Also, Cole's ridiculous overreactions to "doubting" peoples' testimonies, and inability to retract "lies" but not "doubts" (which one sounds like you should be able to back out of?). If he accuses the interviewee of lying and reverts the decision, he ends up looking foolish and defeatist (but it's a valid tactic to make sure "lie" is not the right answer because you suffer no penalty for it). It makes him look like a Good Cop/Bad Cop duo all by himself. The Rabid Cop side in particular became a source of Memetic Mutation literally hours after the game released.
The reason for the big incongruity with the item labeled "doubt" making Phelps just lose it is that in development it was supposed to be something like "force", hence the intense acting for those choices and a few lines of dialogue early on implying he is authorized to browbeat suspects. Had the choice retained its original label, people might not be so surprised about the sudden escalation....
Killing a perp with a human shield is nigh impossible compared to GTAIV. It's not uncommon for them to duck several of Cole's bullets before plugging their hostage for crying out loud!
A trick that always worked well for me was to shoot the gunman in the leg to stumble him, then just finish him with a head or chest shot before he recovers.
With auto-aim turned on, on the other hand, the reticule will be locked on the hostage-taker's head, meaning all you have to do is strike the first time he's exposed, rendering these tough segments a negligible-difficulty button press.
Similarly, car chases: they're obviously scripted for the most part, with chased cars accelerating unusually fast and turning so unnaturally as if they were pulled by an invisible string. This would be more believable if you were chasing sports cars, but some of the chases involve pickup trucks, which are normally the some of the slowest vehicles in the game!
Squick: In abundance throughout the game, such as the Homicide cases, which heavily mimic the gruesome real life Black Dahlia murders, but especially during the Arson case 'A Walk in Elysian Fields' when Mr. Morelli's severely burnt corpse breaks apart. It even freaks out WWI vet Herschel Biggs.
The culmination of the Homicide cases has you bust into a room of the Werewolf killer. There's a bathtub with inside covered in blood and flesh. Needless to say, Rusty finds it as gross as you probably will.
'The Fallen Idol' has you require finding a camera used for recording pornography for Casting Couch purposes hidden behind a one-way mirror, with pictures of girls captured littered around the wall by it. The most recent subject was underage, and the caster is implied to have certainly commited statutory rape numerous times before, likely using the very same room. While that is unsettling enough, optional additional searching around will reveal a room that shows the mirror in the dressing room's bathroom is also one-way...
Ferdinand Jamison is heavily implied to be an example of I Love the Dead, having been found kissing a murder victim. He sees nothing wrong with it when interviewed, and mentions having friends with similar views somehow before Rusty's violent assertions of disgust toward Jamison's opinion cuts him off from elaborating. Carruthers later mentions having fired an assistant who turned out to be a friend of Jamison. Carruthers' job is The Coroner. Needless to say, Carruthers himself mentions "who knows what he could have gotten up to!?"
Visual Effects of Awesome: The new motion capture technology used in this game is put to good use in cutscenes. The detailed facial expressions can make you think you're watching a Live Action movie rather than playing a game.
The tech is designed with the gameplay in mind, having players determine how truthful suspects are during questioning via facial expressions and body language. A possible case of Awesome yet Practical.
Uncanny Valley: The faces of the people in the game are the actual faces of their voice actors. Whether this is creepy or not is up to you. If you're prone to being creeped out by realistic-looking computer animated characters, steer clear of this game. Made worse by the fact that you'll occasionally see NPCs talking to themselves in a very realistic manner, or hurling anger and insults (or flirting) at Cole for no particular reason.
The motion capture for the rest of the body doesn't seem to be as sophisticated as it is for the face (example - the hands are pretty static and don't move until it's necessary, like picking up a piece of evidence), which might make the animation fall into the uncanny valley for some.
The skin of everyone is incredibly smooth, and oddly shiny sometimes. Take a look at your skin and see how smooth or shiny it is.
It seems to have trouble capturing eyes/wrinkled skin. Case in point, John Noble◊.
Ron Perkins◊, who plays Fred Nicholson in the "Nicholson Electroplating" DLC case, is a similar example here.
It can also terrify if you figure out the trick - mainly that they can only animate one face in a shot. It's painfully obvious with the camera angles, only one person talking at a time and the numb expression of your partner doing an interrogation.
Values Dissonance: Cole Phelps' perceived incompetence as an officer is in large part because of the attitudes of the time. Phelps's understanding of Japanese war aims is understandable to us, but incomprehensible to his soldiers. Further, Phelps considered a Bad Luck Charm; there is really nothing an officer can do about such a label. Finally, on Sugar Loaf, most officers would be shell-shocked by seeing their company destroyed before their very eyes; while not medal-worthy, Phelps' going into shock is completely understandable. Jack Kelso's reaction, and Phelps' own guilt over his "cowardice," is more a product of the times they lived in, when combat fatigue and PTSD were not well understood.