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.
Accidental Aesop: It's not clear if the single-player story was meant to even have an aesop, but the Black Side story seems to be trying to say that we shouldn't let emotions get in the way of our lives, and the White Side has a subtle question of whether it's better To Be Lawful or Good. Both of these are made more explicit in the Red Side: Nikolai let his selfishness take over his sense of justice, and was willing to follow a corrupt law instead of trying to do good.
Catharsis Factor: Oh yeah. Feeling in a bad mood? Perhaps go play as Big Bull and grind a load of Mooks into a fine paste. Or perhaps go and play one of Jack's free missions which involves him slaughtering everyone with an explosive rifle. There are several possibilities for catharsis in this game, as with Madworld before it.
While not a Leitmotif for any specific character, Tre-Dot's Ruthless sets the mood for the game perfectly.
Demonic Spider: Cybrid Joes may as well be named Demonic Joes, what with their very powerful attacks, super armor on almost every attack, fiery whirlwind kicks that goes on forever and can kill you in a few hits, and being able to take just as much punishment as they can dish out. On top of that, attempting to grab them is futile. Fighting Cybrid Joes tests your skills (especially the dodging kind), your reflexes, if you remembered to take your rampage with you and your anger management. And if they show up during a multiplayer match, you won't even have the chance to take them on properly as someone will kill you as you try.
Mercifully, in the Campaign, only five of them in total ever appear. Unfortunately, Leo has to deal with three of them at once in the White Side.
Barbot is also pretty popular with the fanbase, to the point that fans wishes that he were a playable character. He also have a small Memetic Badass status thanks to upgraded, Cybrid Arts-capable versions of him making appearances as a fearsome enemy in a few multiplayer modes. Looking closely at their limbs reveals them as being a diffrent model.
Americans Love Anarchy Reigns: Too early to tell, but while Anarchy Reigns has unfortunately bombed in Japan in term of sales, it sold far better in America (Despite not even having been released there yet) even though importing costs 100$ in many cases. Logically, Anarchy Reigns may very well sell well in America.
Unfortunately, the game got a bit of a shaft by the suddenly changing of a release date, putting it right next to big releases meaning it would go largely overlooked.
Fridge Brilliance: Nikolai regains his Killer Weapon gauge if he has the weapon active. This is due to the fact he has a reactor in his back powering his KW.
Genius Bonus: For the average joe, Jack's alligator theme seems a tad random. He doesn't have any overt animal accessories (like Big Bull or Durga) and doesn't make gator puns. Note his name; Jack Cayman.
Good Bad Bugs: The lag in the game can wreak royal havoc on character balance in the game. Some characters gain little benefit while others become obscenely powerful...and then there's Baron, who can One-Hit-Kill on a particularly laggy connection.
Bayonetta has an infamous Killer Weapon glitch, making her incredibly powerful.
A new glitch technique has been discovered, dubbed "Twitch Canceling," which allows a character to cancel almost every normal move into another so long as they have at least one Killer Weapon bar. This effectively gives every character a loop/infinite.
Nightmare Fuel: There's a visual throwback to Madworld within Jack's story, predictably. The context for it, however, is him about to viciously murder a mentally unstable fugitive in the name of his daughter. Just as he spouts his original motto, everything goes monochrome as his eyes glow solid red, and his chainsaw a superheated orange. In one fell swoop, they manage to make the over-the-top killing within the game legitimately terrifying.
"We don't help people. We KILL THEM! I'd ask you to say hi to Stella for me, but you're not going where she is!"
The main reason he is a wonder is because, in the demo of the game, he was one of the playable characters for online mode. Also the most unique character in the demo, being the only robot as well as having the bike form.
Fei Rin and Ai Rin show up in a single mission for the sole reason of picking a fight with Leo. Afterwards they angrily haul ass and are never seen again, unlike Rinrin.
So Bad, It's Good: The voice acting, particularly Zero and Rin-Rin for their hilariously bad accents.
So Okay, It's Average: The music is amazing and some of the character designs are astounding, but combat has numerous flaws and glitches that hamper the in-game experience.
That One Sidequest: "Parasite Infestion" in the second Black Side Stage. Kill 50 Parasites... while dodging the Kraken's tentacles (which hit faster than you can usually follow). Oh, and when you finish that, you have to destroy its tentacles, while being attacked by a Mutant, with what time you have left! Even being the first mission that plays "They Came From Underground" doesn't make it less annoying (not least because halfway through the mission the song is cut off).