Dawn and Lucas' Platinum art has them holding Repeat Balls, because they are repeating their adventure!
In Diamond and Pearl, you can find Hoppip and Skiploom. In Platinum, you can't. The reason? Sinnoh got colder, and the dandelion Pokémon couldn't handle it, so they left. Or...
In Platinum, you can find Absol on Mt. Coronet. The reason? Impending disaster of an inter-dimensional variety.
You may understand Gastro Acid being classified as a Beauty move in terms of Contest Types if you buy into the notion of Japanese being into weird stuff.
Gardenia's fear of the Old Chateau is quite understandable, considering that the Pokemon who live there, the Gastly family, are Poison types. These are strong against Grass-types, which are Gardenia's specialty. And even her Grass/Poison mix Pokemon, such as Roserade, would be weak to the various Psychic-type moves the Gastly line can use.
Why does Caitlin fight you in the Unova Elite Four, but not in the Battle Castle? She probably trains a majority of partners from Unova, which would be unknown to the region of Sinnoh/Johto at the time. It's not hatred of losing: it's the hatred of fighting without her partners.
In a meta-sense, why does the music in Sinnoh sound much calmer than Hoenn? It's because the regions are based on actual real-life locations that are in opposite ends of Japan. In a sense, Sinnoh could be the quiet, Blue Oni to Hoenn's loud, Red Oni.
Cyrus's main Pokemon is a Weavile, a relatively odd choice. Until you realise that, as both a Dark and an Ice Pokemon, it fits as an ice queen- much like Cyrus himself.
At first, it seems like a terribly done Broken Bridge that you can't go to Sunnyshore due to a power outage. However, when one considers it houses an ELECTRIC-type Gym...
Didn't it say in-game that Volkner's Gym was so full of electrical stuff that he singlehandedly caused the blackout?
Alternatively, it was a fault with the solar panels, which double as roads there. So they needed to try to keep people off them until they were fixed.
Additionally, it may seem like Fridge Logic that a town that gets most of its energy from solar panels couldn't get enough electricity to make up for all the power that Volkner supposedly used up. But if one assumes that there was some kind of actual damage to the panels, it's two-fold Fridge Brilliance. First, that they wouldn't be able to gather enough power to fix the outage, and second, it would be unsafe for people to be walking over the bridges.
The Glameow and Stunky lines being uncatchable in Platinum and being commonly used by Team Galactic seems to parallel Ekans and Koffing in Yellow as the two are strongly associated with Team Rocket thanks to the anime.
Why only the south of Battle Zone is accessible? Because since is based on Kunashir Island, only the 2/5 of the island are Japanese. So the protagonist would need to cross a border for accessing the northern half, and because the protagonist is a child/teen, it's unlikely he got the right papers.
We all know how Flint only has 2 Fire-type Pokémonnote Infernape and Rapidash on his team in Diamond and Pearl, since they're the ONLY Fire-types in the Regional Dex. The rest of his Mons consist of Drifblim, Steelix, and Lopunny. They may seem like pretty random choices for "filler" slots, but all 3 do have something to do with the Fire-typing to some extent. Drifblim is a hot air balloon, some of Steelix's Dex entries state that it can dig towards the earth's corenote Which is supposed to be 10,800 F, assuming that Pokémon world's geography is the same as ours., and Lopunny has pretty fluffy fur around it, which would obviously store a lot of heat.note Of course, you could also interpret the reasoning as being something else if you've got a dirty mind.
While it might be a bit of a stretch, why does the Ice-type gym leader Candice have a Fighting-type Medicham in Diamond and Pearl? Well, it could have been a gift from her best friend, Maylene, a martial artist and the local Fighting-type gym leader.
Additionally, in Diamond and Pearl Meditite and Medicham are also an encounter at the Acuity Lakefront and Route 217, both of which are near Snowpoint City. Candice doesn't need to go too far from home to add a curveball to her team.
Why doesn't Pichu have a gender difference like its evolutions, Pikachu and Raichu? It's a baby, of course it would be hard to tell the gender.
One of Cyrus's most distinctive physical features is his lack of eyebrows. Eyebrows are a big part of how humans convey emotion nonverbally, and he despises emotion, so him lacking something that make his emotions easy to understand makes sense.
Why does Cynthia have Garchomp as her ace, aside from the fact that each previous region's Elite Four had at least one personnote Lance used the Dragonite Line in Gens 1 and 2; Drake and Steven used Salamance and Metagross respectively that had a psuedo-legendary? To counter the game's main legendary! Odds are that for many players who got introduced to Pokemon in Gen II or III, taking the main legendary to challenge the Elite Four was a relatively easy choicenote and in the case of Gen III, both Groudon and Kyogre would be very effective against at least some of Steven's team - Garchomp's moveset includes Dragon Rush (to counter Palkia and Girantina) as well as Earthquake and Brick Break (to counter Dialga), meaning that unless you had a second Pokemon capable of countering Garchomp (i.e., an Ice-type) or your legendary was able to outspeed Garchomp, she'd beat you.
It is justified in the 1st Generation as all the trainers you battle in the Pokèmon Tower are Shamans who apparently got possessed by spirits.
Except... it's always the other guy who challenges you. So, they're grieving over their Pokémon dying, and yet make you battle anyway.
Also, many of the items you find in those places get Fridge Horror applied to them. There's something about finding the TM for Return among the graves of Pokemon.
Another thing to consider about Lavender Town: In the original game, it's speculated that you might actually kill your rival's Pokémon, see here.
In Platinum, after you defeat Team Galactic in the Valley Windworks, the little girl tells you, "I think the balloon Pokemon will come visiting again!" The only Pokemon she could mean is Drifloon, who can be found there on Fridays. Drifloon are also said to abduct children. Let that sink in for a moment.
In Platinum, Mr Backlot likes to lie about the Pokemon you can see in his garden. His butler then goes to get the Pokemon, and suddenly, you can catch them there. Where did the butler get them from, Team Rocket? And what if they can't survive there? Is that why you can only catch two of the rare Pokemon at a time? Also, consider that these are mostly baby-Pokemon.
So you just captured Cresselia. Congratulations! You have your very own sweet dreams fuel. No more nightmares, no more waking up in fear, and no more sleepless nights! Everything seems just perfect, right? Except for one little thing... Darkrai. You know, that living shadow, who is essentially a god of nightmares. Yeah, this one that has no control over his power and always wants to be close to Cresselia, since she is the only one capable of healing those who are struck by his spells. And since Cresselia is with you, he will now stalk you relentlessly, day and night, trying to rescue the only being he feels safe with... And remember, he can put you into coma, in which you'll have to live through your worst memories, greatest fears and biggest problems. And only Cresselia, who is trapped in a Poke Ball, can save you. Yeah, better make sure sending her out won't take too much time, or...
The player character could just keep Cresselia out with them at night; considering that she's Sweet Dreams Fuel, there's no reason why they wouldn't. Alternately, if Darkrai does start to stalk them, they could always catch it and just leave it inside a Pokéball instead.
The Distortion World is full of this. Cynthia pretty unsubtly implies this, considering Turnback Cave has been described as a gateway to the afterlife. All those allusions to Satan Giratina has suddenly become a lot more frightening, especially since considering Pokemon's usual Never Say "Die" fare at the time, Arceus probably did a lot more than just banish poor Giratina, considering its Ghost-typing...
And then there's Mira, a little girl you find lost in a very dark cave. Imagine what that must be like for her. Even worse, imagine what it would still be like for her without you coming to her rescue.
Barry, your rival in D/P/Pt, is characterized as a hasty and impatient guy. Then how come he has 2 rare Pokémon in his main team that you can only encounter in Honey Trees, where you have to wait for them to come out?
There's actually an "easy to miss if playing a game, yet easy to see if you take it as real life" way: He put the honey in the trees before he went to bed! The ultimate form of multitasking!
Doesn't still explain how he got the rarest of honey tree Pokemon. (Munchlax has 1% chance on Personal Value specific honey trees.) Of course, he could have just been absurdly lucky, but still.
Maybe he traded for them?
Honestly, trading for them would be entirely in-character for the guy who's constantly mentioned to be impatient. Of course Barry wouldn't want to wait around for that 1% chance!
Or it could be a subtle form of his Character Development considering how late he gets them especially the Munchlax. While he's still impatient he's learned that when it comes to becoming stronger, it's worth it to put in the extra time.
I'm not sure if I read it wrong, but didn't the books in the library in Canalave City say that Pokémon were created (by Arceus) to help humans and that's why we encounter them in the tall grass? I get the helping part when they battle us, since fighting them does level our Pokémon up. And it kind of explains why some Pokémon don't allow us to escape (way too eager to help), but what about the ones that use status effect moves (poisoning, paralysis, sleep, etc.) on our Pokémon? Wouldn't they know that it's painful for the Pokemon and doesn't really help in its level up?
Its just an extra layer of trial for you to overcome. YOU have to heal the Pokémon with something, since few if any Pokémon Moves result in nullifying Status effects.
That story is a myth explaining the backstory of why wild Pokemon appear, it does not state specifically that Arceus made Pokemon for that purpose, it was someone's theory for it explained in-game for why they appear. A separate book does however, appear explaining how Arceus created space, time, dimensions, and created more Pokemon and legendaries in time to shape the universe and world.
There's also the fact that it's an in-universe myth; mythology in our world isn't known for being complete or consistent either.