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: Kamen Rider OOO
Angst? What Angst?: Eiji has no family, job, or ambitions, but he doesn't really attach any importance to those things so it doesn't bug him. However, he's often haunted by memories of a girl he'd befriended on his travels that he was unable to save.
The various theme songs of OOO's forms, whose titles are a play on the combo's name.
#5: "Regret nothing ~Tighten Up~", the theme song of TaToBa Combo. The song is also the default used for the Random Combos that don't have a theme; the TaToBa beats are removed in these cases, of course.
#6: "Got to keep it real", the theme song of GataKiriBa Combo.
#9: "Ride on Right time", the theme song of LaToraTah Combo.
#12: "Sun goes up", the theme song of SaGoZo Combo.
#20: "Time judged all", the theme song of TaJaDor Combo, a duet by Eiji and Ankh.
#36: "POWER to TEARER", the theme song of PuToTyra Combo, a duet by Eiji and Akira Kushida.
Movie War Megamax: "Shout Out", the theme song of ShaUTa Combo.
#38: "Reverse/Re:birth", the theme song of Kamen Rider Birth, a duet by Date and Gotou.
The "Combo Change Medley." If the Combo songs were awesome alone, listen to all of them together in one package.
The movie theme song, Te wo Tsunagou, also counts as a Heartwarming Moment. Doubly so for the full orchestra version.
The OST has a handful of powerful tracks to offer too.
T#50: "Big Brother and Little Sister". As you can guess from the title, it's generally used in scenes involving Ankh/Shingo and Hina. But unlike the other upbeat songs listed here, this one is rather sad and melancholic, and in a handful of instances where it's used in the series, it certainly delivers the emotional weight of the scenes.
Kazari, the Feline Greeed, is a fine example of how a Magnificent Bastard can also be a Complete Monster. Of the five original Greeed, he has by far the most horrifying way of making Yummy, implanting them in their host and controlling their body like parasites; in some cases, the host is conscious the entire time. In the end, they're consumed by it and trapped inside, fully aware of what's happening. If that weren't bad enough, Kazari's actual actions are much worse. He used Mezool, the Team Mom of the Greeed, and Gamel, a Man Child who really doesn't know better, as lab mice to see what would happen if a Greeed absorbs Core Medals that aren't their own and wasn't the least bit disturbed when this resulted in their mutual demise. In fact, he took advantage of it to assimilate their Cores and get even stronger. After that, he begins raising Lost Ankh as his own personal Tyke Bomb and actively helps Dr.Maki try to destroy the world. He did all this with a sick smile on his face (well, in human form, anyway). He's so evil that even his own kind doesn't care about his demise.
Dr. Maki himself also qualifies, but is an interesting version of this as he didn't start out a monster but grew into one through character growth. He does some truly horrible things early on, like helping a Mad Bomber who is hosting one of Mezool's Yummy carry out his attacks to see the Yummy grow, not caring who dies in the process. When the swarm of Yummy hatches, he responds by locking his workers inside with them to see what would happen. Predictably, they slaughter the workers, which Maki doesn't care about. He then one-ups himself by joining forces with the aforementioned Kazari. Later, it seems like he might find redemption when his dead sister is brought up. However, it turns out what he came to believe were false memories and he actually burned his sister to death in her sleep just because she was getting married and would have abandoned him. After he realizes this, he loses all the humanity he had left and willingly sides with Kazari to attempt to destroy the world. This is where he flies past the Moral Event Horizon by absorbing five Purple Core Medals to begin transforming into a Greeed himself. His Yummy so far have been Omnicidal Maniacs and a monster who tears people's dreams apart, leaving them in a coma as a result. What's his reaction to this? He finds it "interesting" and justifies it as For Science! He's just been getting worse and worse since then. Kazari finds out too late that Maki was Eviler than Thou when Maki impales him and rips all his cores out of him, leaving him to die a slow painful (though well deserved) death. He also gives two of his own Cores to Eiji, to accelerate Eiji's greeedification. Finally, he tosses the remaining Core Medals from the other Greeed into Uva to forcibly set his ultimate plan into motion—much to Uva's horror.
Another Complete Monster is the original OOO. An evil king described as "desire incarnate", his goal was to conquer the world and become an immortal god. To achieve this goal, he had five fully sentient organisms created for the sole purpose of killing them off to reach his goal. He then stabs Ankh, the only Greeed who willingly works for him, in the back for his Core Medals. He's so power obsessed that he's called Selfish Evil by a living incarnation of human greed! His own greed ultimately spells his end when he can't handle the power he finally absorbed and is killed by it.
Draco in Leather Pants: The Greeeds: Uva, Kazari, Mezul, and Gamel. In spades. Also, Dr. Maki believe it or not for being utterly hilarious, especially if his doll's knocked off his shoulder.
Ear Worm: The opening theme, "Anything Goes". Despite it being so happy, jumpy and weird compared to the opening themes of Decade and Double, you can't help but listen to it over and over again.
You count the Medals: one, two and three! Life goes on; anything goes! Coming up, OOO!
SUPER, SUPER, SUPER! SUPER TAKA! SUPER TORA! SUPER BATTA!Su~per TaToBa, TA-TO-BA! SUPER!
Ensemble Dark Horse: Akira Date, due to his rather laid-back behavior and general masculinity. Probably why he was brought back for the final eps.
Epileptic Trees: Since the beginning, many people began creating theories about the OOO Driver being a Deadly Upgrade, who the Original OOO was, and how it will effect Eiji, with a popular theory being that Eiji would turn into a Greeed. Surprisingly, they're correct about the latter, but it's not the OOO Driver that's doing the conversion. That would be the Core Medals inside Eiji.
Red, Blue, Yellow, Purple, Whitenote SaGoZo plays around with the white-gray spectrum, but mostly light. and Green monsters, and Rider Forms drawn from their powers? Hmm...
As the Image Song and ending song sung by the main character and his red demonic partner who is the source of power for the main Kamen Rider's red form, "Time Judged All" is, in concept, not unlike "Double Action - Sword Form".
We've had Dr Maki leaving the Kougami company to form his own faction with the younger-looking Kazari and Lost Ankh in the form of a small boy, not long after the fate of a certain otherTwo and a Half Men was in question.
And the final fight is Eiji with Ankh reduced to Core medals vs. Maki, essentially Two And Bits of a Man.
ShaUTa Combo's theme song title, "Shout Out", is bound to make many a troper chuckle.
Birth's theme "Reverse/Re:birth" sounds quite a call back when it is considered that Kamen Rider Blade's resident Gunslinger Garren's actor sang an ending theme for his series, called rebirth.
The OOO chapter in Movie Wars Core is subtitled Nobunaga's Desire, which may bring to mind one of Koei's strategy game titles, Nobunaga's Ambition.
One of those "weird Japanese inventions" often circulated on the 'net involves a device women can use to outwit stalkers, a handbag that unfolds into a vending machine disguise. Which is exactly what the RideVender does.
You know who else was famously disguised as a vending machine? Dispensor.
The animals Kazari's Core Medals are based on, Lion, Tiger and Cheetah, appeared as Mecha in Juken Sentai Gekiranger.
There was quite a bit of negative reaction over PuToTyra, the purple form, being designated as the "Ultimate Form" over the already-impressive TaJaDor (which was touted as such in Movie Wars Core). Fast forward to the finale, and PuToTyra gets Worfed in favor of TaJaDor as Eiji and Ankh battle the Big Badas one being.
There are three possible reasons for this. One, PuToTyra is the same "type" as Maki, so it probably wasn't as effective as against the desire-based Greeed. Two, a true collaboration between Eiji and Ankh is what the series has been building up to. Three, with PuToTyra out of the list, TaJaDor is the strongest form OOO has, as well as the only form available at the point.
Looks like Toei decided to take the initiative here, by churning out Super TaToBa Form for Movie Wars Megamax. It does reuse TaJaDor's head though.
What was the first ever costume theme at the Cous Coussier? Pirates.
Similarly, Hina asks Eiji what he always wanted to be in #35. His first choice? Astronaut.
The Big Bad's motivation is to destroy everything before their "beauty" gets corrupted. Now, are we talking about OOO's main villain or Pokémon X and Y's big bad?
Jerkass Woobie: In #29, when Kazari uses Maki to make a Yummy, it's revealed that his greatest desire is for a hug. Though its pretty much subverted when we find out he's the one who killed his sister because she was getting married and wanted to abandon him. When he remembers this, he doesn't seem all that guilty about it.
Fridge Brilliance: It's no accident that the Yummy created from him hugs women to death. It isn't a case of Does Not Know His Own Strength on the Yummy's part. It's his desire that if someone shows kindness and compassion, they should die before they can be corrupted by the world and taken from him like he felt his sister was.
Magnificent Bastard: Kougami; crazy as he is, makes it abundantly clear that he's in control of the situation in #6, forcing Ankh to accept a crooked deal in order for him and Eiji to use the RideVendors located around the city.
Ankh himself isn't too shabby either: In #20, it is revealed that he switched the core medals with cell medals in the case beforehand so that Kazari's apparent victory by stealing it in #19 was foiled.
Moral Event Horizon: Kazari using Gamel and Mezool in an experiment that could quite obviously be fatal and not caring one bit both were killed in the result. In fact, he smiles while he observes his handywork.
If he didn't cross it by locking his assistants in a lab with rampaging Yummy For Science!, Dr. Maki crossed this when he realizes he murdered his own sister and reacts, not with remorse, but by deciding he did the right thing by killing her and now it's time to destroy the world. It's more likely the latter, as before that point, he wasn't beyond redemption. It's this point that it becomes clear he's irredeemable. Made even worse by the tensing of a Heel-Face Turn directly before it.
Eiji's father crossed this by exploiting the fact his son was badly wounded and emotionally scarred for life by a war his family's money funded to get votes! How could anyone blame Eiji for walking out on his family after that?
However, they are now confirmed to appear in Movie Wars Megamax.
On another topic, OOO's chestplate has been damaged so badly, the Tora Tron Lines were greyed out. It could have been in more scenarios where OOO is in a pinch.
It would have been cool to see Giga Scan combos with other core medals. (In the entire series, only Batta and the Red and Purple ones have been used)
The "Multi-King" form that the Original OOO, Kougami, and the Greeeds try to achieve. Considering how powerful individual combos are (and that Greed!Maki got One Hit Killed by just both PuToTyra and TaJaDor, respectively), it would've been interesting to see the level of power that form would give out.
Unfortunate Implications: At the end of 20 Yasu, the spineless toady afraid of what the newly-freed Yummy host Yamakane would do to him ties him up with rope saying "even if you return to jail you won't forgive me." Had Yamakane not woken up, what was Yasu going to do with him tied up, next to the docks, asleep, if not return him to jail? (And how different would it be from what Yamakane decided to do to Yasu upon waking up, given that it still involved those ropes?)
Visual Effects of Awesome: The last stage of the Final Battle is done amazingly well, especially when they fly inside of the Medal Vessel for the final exchange. They really outdid themselves on this one!
What Do You Mean, It's Not Symbolic?: Kougami's utter fascination with the concept of beginnings and birth; to give a measure, he outright stated his nondiscrimination of the concept, whether the topic of beginning is good or bad. He also makes birthday cakes non-stop while playing Happy Birthday to You... so there.
And on the other side of the spectrum stands Dr. Maki, interested in the concept of ends and death. And his favorite music is Lacrimosa. For those unfamiliar, Lacrimosa is the final movement in Mozart's final work, left unfinished due to his death. It doesn't get more symbolic than that, folks...
According to Kougami, OOO is written as the infinity symbol with an extra 'O' in front. The implications is that OOO's power is a step beyond infinity.
The Woobie: If you didn't feel sorry for Gamel while he was wandering around searching for Mezool like a lost puppy, you don't have a heart.
Gamel again in #45 where he's utterly heartbroken by Mezool discarding him once she's fully restored, and eventually ends up with her dying in his arms.
And again with Gamel in the next episode as he dies and tries to give Mezool's last Core Medal a lollipop and hallucinates Mezool accepting the sweet before collapsing into a pile of Medals himself.