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.
Alternate Character Interpretation: Missingno. is either a unique and interesting Pokémon if handled correctly or a horrifying abomination that will destroy your gamenote Neverminding that it can't actually do that last part.
Breather Boss: Bruno of the Elite Four can be easily taken out by any decent Psychic type. This was true in later generations as well, but somewhat downplayed because: a) Psychic Pokémon were no longer Game Breakers, so players were less likely to have them in their teams; and b) Bruno and other bosses in general wised-up and started utilising other attacking types to counter their weakness.
Captain Obvious: The Team Rocket member in the hideout who says, "The elevator won't work? Well, duh, it needs a key. Who has the lift key?" He asks as if he doesn't know, then after you beat him he says, "Oh no, I dropped the lift key!".
Complacent Gaming Syndrome: The combination glitches, Fake Balance, and the small pool of legitimately good Mons (read: fully evolved and didn't have bad stats) led to the competitive scene being dominated by about 10 of them and lacked any sort of playstyle variation like later generations would have.
Creepy Awesome: The infamous Lavender Town theme is absolutely horrifying, and yet so cool at the same time.
Demonic Spiders: Anything that had Wrap or Fire Spin and was faster than your Pokémon was this. All the opponent has to do is use Wrap over and over to prevent you from attacking (AI players have infinite power points, you don't). This was especially bad with Tentacool and Tentacruel, who could couple it with Poison Sting, doing more damage and potentially losing a Pokémon, as well as Erika's Vileplume, who could couple Wrap with Stun Spore to slow you down so Wrap could work indefinitely even if you were initially faster.
Fandom Berserk Button: Do NOT call Red "Ash" on a Pokémon forum. It will not be pretty. Not helped by Nintendo calling the trainer and the rival with the same names from the anime, before they got the names of Red and Green/Blue in Generation II.
Franchise Original Sin: A lot of fans mock Animate Inanimate Object designs in the later Pokémon generations, particularly Garbodor and the Klink and Vanillite lines in Gen V, saying things along the lines of "Pokémon should be based on animals." These fans completely forget that Gen I had animate Pokéballs, sentient magnets, and living sludge.
X Accuracy in the first games gave every move perfect accuracy. This includes the OHKO instant death moves. The real dangers of this are because beating the eighth Gym Leader Giovanni got you the TM for Fissure which could be used on a lot of final form Pokémon like Dugtrio who could outspeed most Pokémon easily, and because OHKO moves could be used to defeat higher level opponents, it made defeating the Elite Four (barring Lance who could be defeated using a good Ice Beam user, which most Water Pokémon are) a piece of cake. The combination of X Accuracy and OHKO moves was so powerful that the mechanics for OHKO moves had to be changed in future generations so that they could never connect against an opponent whose level was higher than the user's level, and X Accuracy was later nerfed to only give a single-stage accuracy boost that doesn't affect OHKO moves.
In the first generation of games, the Psychic-type was highest on the elemental tier, as Psychic-types only had a weakness to types of attacks that did below-average damage even after being doubled, and there were very few Pokémon with the stats to use moves of these types anyway (and due to a bug, one of those types actually didn't affect Psychic-type at all, rather than do double damage). And also by the fact that in Generation I, the most common type was the Poison-type (which is weak to Psychic-type), with 33 members, just narrowly beating out the ever-common Water type (32 of the Generation I Pokémon). In later games, the Poison-type Pokémon count fell to the back so far that it was tough to remember why Psychic was ever such a powerful type to begin with. The Psychic-type advantage was made worse by the fact that the stat Special governed both Special Attack and Special Defense. This meant that Pokémon with high Special, such as Psychics, were much more useful than Pokémon with low Special, such as Fighting. This was fixed in later generations by separating them.
Anything that can learn Wrap, Fire Spin and Clamp turned up into this back in the Generation I games, especially because almost all of them have decent speed stats. See Demonic Spiders above for more details. Probably why the moves are nerfed for the future games.
Genius Bonus: The Magikarp line is a reference to a Chinese legend that states that if a carp can jump over the Dragon Gate (believed to be at the top of various waterfalls), it will be transformed into a dragon as a reward. This holds more ground when Pokémon Snap shows a Magikarp jumping into a waterfall and emerging as a Gyarados.
Genius Programming: No game of this size had ever been squeezed onto the Game Boy's cartridge before. The Good Bad Bugs in the game mostly came from all the shortcuts the programmers had to make to achieve this.
Hyper Beam does not require a recharge if it successfully KO's a target or destroys a Substitute. Fixed in Stadium.
Selfdestruct and Explosion will not knock the user out if they destroy a Substitute, though their sprite will disappear. Recoil from moves like Double-Edge is also negated when they destroy a Substitute.
If a Pokémon that had just used Hyper Beam is targeted by a Sleep-inducing move before it gets to move again (i.e. before it can activate the "has to recharge" message), the Sleep-inducing attack will always hit and even overrides any status the Hyper Beam user may have.
Psychic-types are actually immune to Ghost attacks when they are clearly supposed to be weak to them.
Leech Seed does extra damage if the target is also inflicted with Toxic Poison.
Haze will cure opponents of any status effects and Leech Seed, and resets Toxic Poison to regular Poison on the user.
HP recovery moves will fail if the user's HP value is 255 or 511 below their max.
Agility and Swords Dance negate the stat drops from Paralysis and Burn, respectively, before applying their Status Buff.
Focus Energy and the Dire Hit item will actually reduce the chances to crit to a quarter of the previous value. Fixed in Stadium.
Substitute does not protect the user from being inflicted by opponent's Standard Status Effects expect for Poison and it also takes Confusion damage instead of the user. The first part is fixed in Stadium.
Status Buffs can roll over to actually lower the stat after they reach a certain point.
If a Pokémon takes Confusion damage or is fully Paralyzed during the invulnerability turn of Dig/Fly, they will remain invulnerable (and be able to attack) until switching out or using Dig/Fly again.
The Master Ball can actually fail since it uses the same check as 100% accurate moves.
The Mew Glitch lets you get any Pokémon in the game by abusing an exploit that lets you escape Trainer encounters before they fully initiate with Fly/Teleport. "Any Pokémon" includes the eponymous Mew (which is otherwise unobtainable) if you do the glitch in a specific way.
The Old Man Glitch is one of the many ways you can encounter Missingno., and easily the most well known. It's caused by talking to the Old Man in Viridian City to activate the catching tutorial, then immediately using Fly to go to Cinnibar Island and Surf on the east coast of the island. This will trigger an encounter with Missingno., one of several non-glitch Mons, or a glitch trainer depending on the player's name, since the water tiles on that coast of Cinnibar have incorrect encounter data.
Growing the Beard: Pokémon Yellow actually is a better game than Red and Blue in terms of gameplay, as the majority of bugs, glitches, and imbalances are fixed, and the way is paved for the full beard-growing of the franchise with Gold and Silver.
Harsher in Hindsight: In the Pewter City Museum, there is a model of the Space Shuttle Columbia, which disintegrated in 2003. While it's still explicitly referred to as such in the Japanese version of the remakes (since the Japanese versions were released before the accident happened), in the English version, it's simply referred to as "Space Shuttle".
A Lass outside of the Rock Tunnel complains that there should be a pink Pokémon with a floral print. Now that Black and White are out... Given the reported number of unused designs for Pokémon, many which got used later, it could easily have been an In-Joke at the time.
One of the little quirks of the Missingno. glitch is that, due to not having a back sprite, he'll appear as the last pokémon loaded into memory. This later became Zorua and Zoroark'ssignature power - they'll appear as the last Pokémon in the team.
It Was His Sled: The existence of Mew. At the time of the game's release, not even Nintendo was aware Mew was programmed into the game. It quickly became one of the most well-k
Lance of the Elite Four derived a lot of his difficulty from using Dragon Pokemon, which resisted many common types (including the primary types of all the starters) and were so obscure that they were almost never encountered in actual battle. A player had to know the type chart really, really well in order to realize that Ice was their one practical weakness. Anyone who has played almost any Pokemon game from Generation II onward is pretty likely to already know this.
It's hard to remember now but Blue being the Champion and Giovanni being the last gym leader were originally spoilers.
Misty's Starmie is incredibly unfair for the part of the game she's encountered in. It's one of the most powerful Water-types in the franchise at this point that you're fighting as the second boss, plus its Speed stat gives it a high crit rate so it can potentially beat you even if you have Bulbasaur/Ivysaur to tank its Bubblebeams.
Sabrina. Psychic is a Game Breaker and she has 3-4 depending on whether you're playing Red and Blue or Yellow, and in the latter her team was beefed up to level 50. Her Alakazam also has Reflect (which in these games is permanent until the user switches out) and Recover so it has no trouble tanking hits despite what its Squishy Wizard stats may suggest.
Lance, the fourth member of the Elite 4. Three of his Pokémon are Dragon-type, which are only vulnerable to Ice and Dragon, and resistant to all fournote Grass, Water, Fire, Electric (in Yellow) starter types. As this is the first (and only) time that particular type is fought in the single-player game, it is entirely likely that the player doesn't have an Ice-type Pokémon or move prepared, nor is there a Dragon-type move that can be used against them — the only Dragon-type move in the game, Dragon Rage, deals a fixed 40 points of damage, and ignores type.
Base Breaker: Just like Lyra from HGSS, Leaf suffers from this. Don't get into a conversation on whether or not she exists in the game universe.
Scrappy Level: The Sevii Islands, which are often regarded as a Filler Arc that offers very little to do and only exists to show off a couple new features that weren't in the original Red/Blue/Yellow versions.
That One Sidequest: Obtaining a Lucky Egg in this generation. It's a hold item that boosts EXP gained by 50%, making leveling much easier. However, it's only held by wild Chansey. While you could use Thief to steal the item in other generations, in this generation Chansey only appears in the Safari Zone, meaning that you have to actually catch the Chansey. They're rare, hard to catch, quick to flee, and only have a 5% chance of actually holding the Lucky Egg, making it nothing but a Luck-Based Mission. Most players didn't even bother.
Professor Oak's infamous line: "I came when I heard you beat the Elite Four."
Ekans = snake, Arbok = cobra, Muk = ???
Alternate Character Interpretation: In one "interpretation", your rival is the good guy. note In Lavender Town, he asks you "What brings you here? Is your Pokémon dead?" before challenging you, without explaining what he's doing there. You then fight him, and if you've been paying attention, you will notice that he no longer has a Raticate. The theory is that the player character wounded their rival's Raticate so severely that it died of its injuries, spurring him on to beat the Elite Four before the player. But shortly after he has defeated the Elite Four, he must fight the player...who defeats him...and then is congratulated by none other than his grandfather, Professor Oak, who scolds Blue and claims he lost because he did not treat his Pokémon with love and trust. This gives the fairly one-dimensional rival character a deep story and portrays him as a tragic hero with terrible luck. It also makes your character's actions fairly despicable, as all this guy wanted was to be a great Pokémon trainer and win his grandfather's love. Easy to poke holes through this. This does require some big assumptions, though, and doesn't change the fact that he acts like a Jerkass towards you.
Professor Oak has had a few theories devised about him over the years. The first type of theory is that he's a Genius Ditz who understands Pokémon but is too stupid to keep all the data about them (or, indeed, remember his own grandson's name), hence why you have to recollect all of it. The second kind of theory puts him in a somewhat more malevolent light, either as having some illegal ties to the various villain teams or as the Bigger Bad of the franchise.
Americans Hate Tingle: Grimer's and Muk's French names of "Tadmorv" and "Grotadmorv", which are condensed versions of "pile of snot" and "big pile of snot", are unpopular with French Canadians. At least one of the two is guaranteed to come up whenever there's a Dub Name Change debate with Quebecers.note This trope applies because the French translations of the games come from France, and weren't even available in Quebec for the longest time.
Germans Love David Hasselhoff: In contrast, Blastoise's French name of "Tortank" is popular with English-speaking fans, having earned special mention on a number of blogs and a Dorkly popularity poll. Since it's derived from "tortue" (which is similar to English "tortoise") and "tank", it can easily pass as a cooler English Pokémon name.note However, the actual French pronunciation is more like "toghr-TONK", not "TOR-tank" (admit it, you probably just read it as the latter).
Dragonite. It's the original pseudo-legendary, and one of the best Dragon-types in the game... that just happens to look like Barney the Dinosaur. The fact that it bears little resemblance to its serpentine pre-evolutions doesn't help matters. Plus, just like Charizard, all the worship it gets from fans who only like the first generation annoys some fans of the newer gens. This may be why they gave Iris' Dragonite a grumpy personality and a generally angry expression in the Black and White anime season, to defy its cuddly appearance and help "unify" its popularity. Incidentally, Red/Blue are the only games in which it is shown with an angry expression, aside from its attack animations in Pokémon X and Y; in fact, every Dragonite card in the TCG from Dragon Vault onwards has shown the Pokémon with a serious expression on its face.
Pikachu, for all of being the series' mascot, sees a lot of abuse both from people tired of seeing Pokémon everywhere, and from fans who feel it gets far too much attention.
Charizard, despite being one of the most popular Pokémon designs in the series for its dragon-like appearance, is regarded in fandom circles as a symbol for "Genwunners" — people who prefer the first generation over any other, and are often perceived as doing little but complain about later games. Essentially becoming the Pokémon equivalent of Wolverine in terms of popularity and exposure doesn't help matters on either end of the spectrum.
Breather Boss: Giovanni is rather easy for being the final Gym Leader, since most of his Pokémon are rather slow and all of them have common weaknesses, or even double weaknesses. Even more so in FireRed and LeafGreen, where his strongest Pokémon in the original Red and Blue — Rhydon — was replaced by its unevolved version, a Rhyhorn, of all things.
Draco in Leather Pants: Giovanni gets this from some people claiming he wanted to "stop" Mewtwo by using the Silph Scope to obtain a Ghost to fight him and (when that failed) use the Master Ball to capture it. There's no evidence to suggest Giovanni even knew Mewtwo existed outside of the anime (which isn't canon to the games) and the games never explicitly mention why Team Rocket was at Sliph in the first place, so this relies on a lot of Fanon. While Pokémon Origins confirms that they were there for the Master Ball, Giovanni's charactization makes it clear that he's Only in It for the Money and Mewtwo isn't mentioned until after Giovanni's episode.
Although most of the original 151 Pokémon have become highly regarded in comparison to later additions over time, and a handful having reached superstar levels, at the time of the release of the first generation several Pokémon in particular stood out apart from the starters and Pikachu:
Mewtwo, the strongest Pokémon in the game. It is caught at level 70, has a sleek, alien look to it, and outclasses every other Pokémon in the game in pretty much every way.
Alakazam is one of the strongest Pokémon in the game, as it is Psychic, has an excellent moveset and great stats. It is often replaced by Mewtwo, which is better in almost every way, but by the time the player gets that far, Alakazam will have been in the player's party for most of the game. As a result it is very fondly remembered.
Gengar is a nasty-looking Ghost-type Pokémon with excellent stats and a cool, creepy moveset. As its evolutionary line is the only set of Ghost-type Pokémon in the game, its immunity to Fighting- and Normal-type moves also helped set it apart. This is particularly noteworthy for the originals, as Ghost-type moves didn't work on Psychic Pokémon owing to a case of Good Bad Bugs.
Scyther is a ninja-esque version of a praying mantis, with its scythes being actual metal blades. Thanks to its badass appearance, it quickly became a fan favorite, despite its rarity.
Eevee and its "Eeveelutions" became highly popular for two reasons: first, allowing more than one evolution was a mechanic unique to Eevee at the time, and second, the Eevee-related Pokémon are one and all considered to be adorable.
Gyarados is one of the most physically intimidating Pokémon in the generation, being an enormous, very angry-looking sea dragon. Having come from the incredibly weak Magikarp makes it particularly memorable.
It's probably not a coincidence that all of the above evolutionary lines except the Eeveelutions received Mega Evolutions in Generation VI.
Jigglypuff is a cute pink normal and fairy type that thanks to its popularity has been in every Super Smash Bros game so far.
Evil Is Cool: To the dismay of many players, there is no "yes" option when the Rocket grunt at the end of Cerulean Bridge wishes to recruit you into Team Rocket after seeing you battle.
First Installment Wins: The first games, and the original 150 (+1) Pokémon are pretty much synonymous with the series. The starters are always compared to Charmander, Bulbasaur, and Squirtle, the original 150 typically dominate the popularity polls, and Red and Blue/Green Oak are the most well known protagonist and rival respectively (behind theiranime counterparts, Ash and Gary) and, thanks to the games' Popularity Polynomial compared to the anime, possibly the most popular. Despite all the glitches, general messiness and "Genwunner" backlash, there's little doubt that the originals are the most well-remembered and generally liked among fans both new and old (mostly due to the Pokémon fad at the time of Red/Blue's release, and the fact that it's more common to find fans of newer gens who are accepting of older 'Mons than the other way around).
Goddamned Bats: Several examples. One thing that most have in common is that they appear in places (caves, open water) where you cannot avoid encounters by simply staying out of tall grass as they can appear at any time.
Zubat: They, along with their evolved form Golbat, appear in every cave in the game (you pass through no fewer than four different caves to complete the game). They're not particularly powerful on their own, but their encounter rate is annoyingly high, they're fast (which makes fleeing from the difficult), and they will gleefully confuse your Pokémon with Supersonic at lower levels and the more-accurate Confuse Ray at higher ones. Come the remakes, they're even given the Ghost-type move "Astonish" at low levels and Bite, which they have at higher levels, is reclassified as a Dark-type move, potentially hurting Psychic-types (which are strong vs. their Poison-typing) if you're trying to use them as a counter.
Tentacool: They're basically the Zubats of the sea. You'll run into them while Surfing everywhere. They have Supersonic to confuse you just like Zubat, and add in the ability to poison your Mons as well with various Poison-type attacks while trapping them in battle with Wrap. Another issue with them is that they appear at a wide-variety of levels randomly. Running into that level 40 Tentacruel after mostly battle Tentacool with levels in the high teens even becomes a Boss In Mooks Clothing encounter.
The fact that Giovanni, the boss of Team Rocket, is also the Viridian City Gym Leader is all but common knowledge among fans of the series who have never played the game. Strangely enough, once you enter the gym, and read the plaque on the statue, it says right there it's Giovanni. And, yet, the character who often greets you at the entrances of the gyms claims he has no idea who the gym leader is!
Your rival beating you to the title of champion and being the True Final Boss after you beat Lance is common knowledge in video game circles.
But it was still news to NintendoCapriSun in his blind LP (well, different generation, but every game follows the same formula).
The Scrappy: Mr. Mime and Jynx are widely disliked by the fandom for their disturbing designs. Fans of the newer gens also tend to criticize Gen I Pokémon with overly simplistic designs such as Diglett, Magnemite, and Grimer (though evolutions introduced in later gens such as Magnezone tend to alleviate this somewhat).
Unintentionally Sympathetic: Sure, Blue may have been a cocky jerk who got what he deserved by losing his title in mere minutes, but having his grandfather come over just to berate him for not caring for his Pokémon? That's cold.
The Woobie: Cubone. You would be too if your mother died after you were born, you couldn't look at the moon because you could see her face in it, and you had to wear her skull to hide your face.