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.
YMMV: Warriors Orochi
Awesome Ego: Taigong Wang, who, while frequently boasts about him being great and magnificent, is indeed an incredibly powerful individual (being a Mystic and all), comes up with numerous strategies for his allies that usually succeed (depending on the player's in-battle performance), and his view of humanity is summed up thusly:
Taigong Wang: ...I know how strong you humans are. With your combined might, there is no enemy that you cannot defeat.
Crowning Level Of Awesome: The DLC stage in 3 titled "Speed Is Of The Essence". In a nutshell, you are alone, and facing you are tons and tons of constantly respawning enemies. Your goal? Kill as many enemies you can to trigger the appearances of unique generals up until Orochi X, all under 15 minutes. Tons of kill counts, no allies to worry about, no missions to hinder your performance, and the time limit can be eliminated using the Musou Battlefields.
Character Tiers: Based on character safety, and stage completion time on a stage with proper testing conditions. In general, in a Tier list, the Top Tier upwards qualified as a Gamebreaker in their own rights with the God/Broken/S+ Tier and the upper of Top tier as those considered over the top broken. Naturally, the list are reserved for the most efficient and destructive characters(1!Diao Chan, Kunoichi, 2!Huang Zhong, 2!Cao Ren) or a design flaw(Sun Jian).
The third game plays with this. The world-destroying Hydra is essentially Orochi's power unchained, but at the same time you get to recruit the personification of Orochi's conscious into your party.
Ensemble Dark Horse - Mizuchi/Diamondback is slowly becoming this, due to the ridicously profuse amount of screen-time he gets in the third game, despite being a generic officer who never became playable (unlike fellow generics Gyuki and Dodomeki). His Small Name, Big Ego attire certainly helps too.
Fridge Brilliance - If you notice and look closely, each face of Orochi, Shuten Doji, and Yinglong looks similar each other. Furthermore, if you compare Yinglong's theme to Orochi X's, you will recognise that they share simliar passages.
Game Breaker : Tons of it. The weapon system in general is this. Amongst the character, the most stand out example are Kunoichi in first two games thanks to her fast offense and Invincibility loop, Diao Chan in the first game, Cao Ren and Huang Zhong in the second game, Sun Jian in both games, and most Dynasty Warriors cast in the first game. Orochi himself counts, as long as you only used his first triangle attack.
Sun Jian takes a special note as the Top of the tier list and being broken in a rather different way. His special move allows 10 seconds of infinite musou bar usage at cost of health, which has TONS of usage including spamming Triple Musou or any Musou based move that is normally limited into a couple of uses. Sun Jian is not simply "broken" he is a massive design flaw of a character that can easilly broke every character in the roster.
Just like in its home series, Ryu Hayabusa's Izuna Drop. It launches Ryu and the enemy upwards, thereby making him safe from damage, and then the poor schmuck grabbed by Ryu would get piledrived to the ground and causes a ground pound effect for area damage... Note that Ryu is invincible and uninterruptible when he's piledriving and due to him being a Power character, he has less chance of getting staggered and interrupted. And unlike in home series, the AI isn't so overly sadistic-tear-your-hair-apart level so you'll be able to land this move perfectly... A LOT.
In the Versus Mode on Warriors Orochi 2, the list of characters with at least one move satisfying this trope actually outstrips the list of characters too horrible to even use. By quite a margin at that.
From the third game, while there's tons of broken characters, one character is agreed upon to be the single best character in the whole game, Xiahou Ba. His Special Move increases his attack and movement speed to a ridiculous degree and also works as an Invulnerable Attack, he wields a BFS and can shoot huge Sword Beams and shockwaves out of it twice in succession, and with a maxed out Osmosis, you can easily gain back the amount of Musou the move costs to use by the time it runs out. All of this translates into making him a Lightning Bruiser with insane offensive power.
The defensive equivalent is Xu Huang, whose EX attack gives him an aura that makes it so that everything only does Scratch Damage to him, even on Chaos where enemies can kill any other maxed out character in 4-5 hits. Since it's an EX attack, he can spam the combo that leads into it all day and use it to beat most stages with little effort. The fact that his attacks have an unique property of getting any enemy he hits stuck into his axe so that they can't escape any followup hits and take full damage from them doesn't hurt either.
There's also a number of generic Game Breakers available for all characters: using a rare skill that makes all elemental skills activate on every hit as long as your Musou bar is full, meaning all your attacks are unblockable, kill mooks in a single hit and do a percentage of damage to anything stronger on every hit, or using one of the 2 characters that block attacks while attacking and giving them equipment that allows them to block attacks from any direction and recover life when blocking.
In the third game, you can access the most Egregious example by far, in the 'Triple Thrift' combo. The 'Thrift' ability reduces the consumption of the Musou Gauge, and is possessed by two characters from the Samurai Warriors series - Nõ and MotochikaChõsokabe. Combine them with a Thrift-using character from another series (Your choice of Dong Zhou, ZhangJiao or LiuShan), get them all to Proficiency S, and your Musou-gauge will decrease at snail's pace, allowing the Samurai Warriors-flavor Musou (which is normally a brief Super Mode) to last pretty much an entire battle... making you entirely invulnerable until it runs out, and since you can refill your musou just by hitting enemies with charge attacks with the right weapon skills equiped, it never will. And if you DO get knocked out of it by a cutscene, a bath, or a slide down a mountainside, you can just switch to the OTHER character and jump right back into invulnerability. Makes Chaos Mode a walk in the park, if somewhat dull...
Porting Disaster: While the Wii U version is by no means bad, it does have some draw-distance issues that make soldiers seem to pop up right out of nowhere.
HoYay/FoeYay/LesYay - Zhao Yun & Yukimura, Cao Pi & Mitsunari, Sun Shangxiang/Xingcai & Inahime, to name a few... Koei games in general are built upon these.
Himiko and Da Ji are pretty cute also... In one particular mission in the second game, you overhear a concerned Da Ji desperately screaming for Himiko to escape from the Shu forces. Himiko expresses concern toward Da Ji taking this battle all for herself. And, in the last chapter, Himiko will pray for Da Ji's safety if she engages in battle.
Don't forget about Cao Pi (in the first game) and Cao Cao (in the sequel).
Scrappy Mechanic - I get to control three characters, but why is it when the character I control dies, it's an automatic game over? What becomes of the other two?
The first two games forced your co-op partner to use the same team as you. Thankfully changed in Z (albeit not released internationally) and 3.
So Cool It's Awesome - Worth noting that WO3, barring that one chink of no English VA, is thus far, the highest rated, most praised Warriors game ever that even the reviewers that usually hated the 'repetitive' Warriors games caved in for praise, considering it the ultimate definition of Warriors/Musou games.
Surprisingly Improved Sequel - Warriors Orochi 3 is probably the best Koei "Warriors" game yet made, highly rated even by reviewers who usually say they hate the repetitiveness of the franchise. For the Orochi sub-franchise especially this is significant because WO2 got only middling scores at best. Why? A variety of little reasons; inclusion of many characters beyond just Samurai/Dynasty Warriors (like Ryu Hayabusa and Joan of Arc!), better combat variety between characters in general in form of giving different charge attacks to everyone so that the only shared move between characters that use the same weapon is their basic combo, the hundreds of unique conversations in the camp between your characters, and most likely the mission progression. Instead of having a few story modes for different sides, everyone the player controls is on one side and you add more and more guys to your collection with each stage you conquer, leading to an addictive Gotta Catch 'Em All mentality.
That One Level: WO3 has at least 2: Battle of Ueda Castle has a disproportinately high number of allies you need to protect which tend to be positioned far apart from each other, and since it's the second actual stage in the game not counting the intro level, you really don't have many leveled-up or otherwise overpowered characters to help you out, which can easily lead into one of the allies getting killed while you're busy trying to save another one.
The second one is Battle of Xuchang, due to how easy it is to lose if you don't know what happens beforehand: one of the main objectives is capturing Shuten Doji, and the second you kill off Dong Zhuo, he'll start fleeing. Since he's positioned very close to an escape point, it's extremely easy to fail to get to him in time before he runs away which causes you to lose the mission.
Rescue at Osaka Castle from Wu's campaign in the first game is unanimously hated among players. Basically, you need to rescue Sun Jian and a few other generics, who are kept separately in each of the castle keeps. Sounds easy enough, except that the keeps are scattered all over the castle, have multiple levels and are barred by closed gates, meaning that you have to circle around all the way from one end to another just to get to them. What's more is, once Sun Jian has been rescued, you still need to escort him to the escape point, dealing with incessantly appearing ambushes and seal off every enemy entry point along the way, or else he refuses to move a single step, adding unneccessary frustrations and overall just makes the level look like a blatant Fetch Quest. No need to mention that at the end of the level, Sun Jian still gets himself re-captured, which just make you feel your efforts are all in vain.
Wu's other levels are no better, either. Half of them are filled with overly long banters that do little more than delaying scripted events (Gate opens, route cleared, etc.) thus slow down your progess, while the other half throws in egregious amounts of Escort Missions or stages in flames/filled with poisonous air that gradually eats away your health, earning lots of resentments from the players.
Tier-Induced Scrappy: Ho boy, WO3 sure did a number on Goemon compared to the previous games. Since he's now a Technique-type character instead of Power, all he gains is an useless sidestep instead of Super Armor he desperately needs to offset his laggy attacks which are the only way to trigger his weapon attributes, which doesn't help him much considering his attacks are lacking in range and mobility to begin with. His attack properties were also changed so that it's difficult to deal large amounts of damage to officers without knocking them away, his special attack is extremely difficult to connect with and his buttbounce has a tendency to make knocked down enemies stand up if it hits them, allowing them to resume attacking Goemon before he manages to recover, basically making it so that you're always an accidental button press away from a near-guaranteed suicide if you ever try to play as him on Chaos for reasons stated above.
Gyuki is also this in 2, due to the fact that all his moves are so slow, on higher difficulties, it's almost impossible to finish off an officer before the surroudning mooks do it to you. You can try to equip skills that are normally considered Game Breakers on him, and it still wouldn't have helped much.
His attacks in 3 are still ridiculously slow, but it doesn't matter much thanks to his air charge attack which were introduced in the third game: it is by far his fastest attack, causes a huge shockwave and activates elements, allowing him to dive into large groups of enemies with reckless abandon and come out on top.
Noh is seen as this for the first two games thanks a having little reach and large start-up times for her charge attacks. 2 damaged her even further by removing any stun effect from her 'Needle' special, the only move that stopped her from becoming unplayable on the hardest difficulties. Thankfully she managed to get a speedboost in 3, helping her out of this position.
Magoichi Saika, like Noh, is hurt badly by short-ranged moves and long start-up times. However his first charge attack in 3 saves him from the bottom-rank for having elemental attributes on every hit and being able to leech large amount of health/Musou with the right load-out.
In the Japanese version of the game, Orochi Army's generic Demon officers are all named after famous monsters or supernatural beings from Chinese and Japanese mythology. The English version gives the generic fanged demons names of various snakes, Gyuki-type demons have names of minerals, and Dodomeki-type demons are named after different types of spiders. Similarly, the Mystic generiecs in the third game are named after constellations, as opposed to Chinese and Japanese mythological figures in the original script.