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.
The Subjective Tropes have appeared. It's the killer. Do not die.
Concerning Catherine: is she a malevolent entity who has willingly led several men to their deaths at the behest of Mutton? Or is she merely a Punch Clock Villain who has found someone she genuinely likes in Vincent?
Base Breaker: Erica, good god. Many people were riled up by the fact that she is a transsexual and how she's treated. Although it may be somewhat noteworthy that most of these complaints come from people who haven't played the game yet.
Katherine also has shades of this, due to some of her actions. Speaking of which, Catherine has shades of it, too...
"Hilarious" might be an overstatement, but some scenes become amusing when looked back on with the knowledge that Catherine is a succubus, and Invisible to Normals:
When Katherine showed up with the cake while Catherine was over, she couldn't have seen Catherine anyway... and when Catherine went into the bathroom, she was probably just eavesdropping from there and waiting for the most inopportune time to flush the toilet.
When Catherine showed up at the Chrono Rabbit while Vincent was there with Katherine, she was probably just hanging out in the entryway, shouting things in Vincent's direction.
It's Hard, so It Sucks: You know something's hard when the masochists that are the Atlus fanbase have so much trouble that Atlus had to patch in an easy mode.
Hell, Bennett The Sage of That Guy with the Glasses, often shown to be a rather... unpleasant fellow in crossover vids (all played for laughs of course. He's nothing like that in real life) couldn't even get through the game and come time to review it, most of his video on it was him complaining about the difficulty.
Worse. There are nine stages of climbing, eight of which have these bosses. However, from a certain standpoint, Shadow of Vincent and Thomas Mutton/The Dumuzid are the worst. It's not just their designs that make them scary. In these "boss fights" these two are circling the stairway as Vincent climbs. Not climbing after him, CIRCLING him!! Now, it was bad enough for the poor guy when it had to outclimb the ones chasing him up. The horrible realization sets in that these particular foes are playing with Vincent. And it STILL gets worse!
Not to mention that Shadow of Vincent at one point turns the entire stage pitch-black, save for his creepy-ass grinning mask, and will kill you instantly if you don't climb fast enough. Oh, and then he eats another dream-climber, Steve, right before your eyes.
The Sheepmen. What happens after they die in the dreamworld. The looks on their faces, they even still got the sheep eyes.
Periphery Demographic: Surprisingly, the game's multiplayer mode has become popular amongst competitive gamers, to the point where in some locales, there is a tournament scene for the game.
Unfortunate Implications: There are some issues with the meter, which symbolizes Freedom/Order, not Good/Evil (as the game leads you to believe until the end). While some of the choices seem far less unfortunate once this is known, some... still don't. Rather sexist answers tilt you towards "Order", implying that a pro-marriage person doesn't really believe in gender equality.
That and some of the more Jerkass options push you toward "Freedom".
To be fair, however, Vincent himself acts like it's his fault as well. He thinks he intentionally chose to have sexual intercourse with Catherine, so he describes his own behavior to his friends as though he's cheating on his girlfriend. So that's why they act like it's his fault, because Vincent himself thinks so.
Erica, the spunky waitress. It's not her character that's problematic, but everyone else's treatment of her. Nobody seems to care that her boss is sexually harassing her, Vincent and his friends act derisively towards her for her female identity, and Toby is actively discouraged by others from pursuing her romantically, all simply because she's a transgender woman.
The idea that having sex with a transgender person is disgusting is played for laughs.
To be fair, however, Erica is never explicitly called transgender. The big reveal is done in a single throwaway line in Katherine's True Ending, when Toby complains that the guys knew her as "Eric" back in school and didn't tell him before he punched out his V-card; without the additional subtle clue that Erica also got a supposedly male-exclusive nightmare, Toby's line could also mean Erica used to be a huge tomboy or something.
The game's ideas about the sexual politics of relationships and marriage, which seem to be that women only get into relationships for the ultimate purpose of marriage ("It may be a one night stand to a man but to the woman it is the begining of a whole life together" to use the words of a certain someone) and men are immature manchildren who will do whatever they can to avoid this commitment, are also somewhat dubious. It also seems to believe that the only purpose of marriage is to make babies.
The Untwist: Catherine is a succubus. Who honestly didn't see that coming?
Why Would Anyone Take Him Back?: Justified! During the course of the main game, Katherine breaks up with Vincent for pretty justifiable reasons. So, since you can get a Katherine ending, there has to be a good reason why Katherine would ever take Vincent back...and lo and behold, it turns out Catherine was an illusion and Vincent never really cheated. Although it sounds like bullshit at first and Vincent's friends have to back him up for the explanation to stick.