MAIN STORYA billion words have been written on the stories, characters, and critters in the Pokémon games before, and I do not have much more to say, so let's keep it simple: Pokémon is a beloved and long-running franchise with numerous sequels and spin-offs that all mostly adhere to the same narrative frame: You, a homeless child, skitter recklessly through the woods, collecting creatures and forcing them to fight one another for personal or pecuniary gain. Periodically, when you emerge slavering and unwashed from the deep wildernesses, you encounter small bastions of society where polite people train at gyms. In order to advance your quest to collect 'em all, you must battle the managers of these gyms to collect magic jewelry that allow your pukimanz to use new powers and inflict new harm on the innocent wild creatures of the world. Eventually you must prove your efficacy at animal-fighting with a bunch of other cruel psychopaths at the Elite Four or some such final-encounter, and then...you are the bestest trainer? In a nutshell, that is it. As far as I know, each generation fleshes out or expands on the world, and sometimes lets you travel between different regions, but don't break that mold much. Later games do have more going on narratively, but today we are keeping it to Gen. 1.
In all seriousness, the game's narrative is about a boy (specifically) on a quest to catch monsters, become a hero, and become the father he never had to a bunch of animated toys from the Island of Misfit Toys. The main narrative--the thing you pay attention to most directly--is really just a frame to advance your monsters from level 1 to 100.
KEY SIDE QUESTSAlthough the gotta-catch-em-all narrative of gym badge and pokédex completion is the one the game spends the most time on, with the scant civilization of Kanto structured around gyms and areas of increasing difficulty (thank the poké gods we do not start off with a lvl 5 bulbasaur on Cinnabar Island...), the real meat of the game's storytelling is actually in a series of side-quests that flesh out the opposing force in the story: Team Rocket.
Yes, while a player might confuse Professor Oak's grandson and the player's rival as the antagonist, this is actually not the case. The Rival is a foil to the protagonist, and typically exists to highlight particular qualities of the protagonist. Sometimes a foil might receive a tragic ending to demonstrate how two similar people can wind up in dramatically different places, and sometimes the foil's success is used as a carrot. This is the case with the Rival in Gen. 1. The Rival is always a step ahead of you in the world, even if his pokémon are not. His flippant ne'er-do-well nature also contrasts the apparent care the player has for his own roster. The Rival is out for the same goal, but with less compassion and more aggression.
That makes Team Rocket the real opposing force. Led by Giovanni, a BOSS who turns out to be the eighth gym leader, Team Rocket is not the bamboozled duo we see in the anime. The various schemes the player foils through the game are actually pretty heinous, when you consider the context: a children's game. Initially, the player runs into Team Rocket at Mt. Moon, where they have basically put this thoroughfare cave on lock-down so they can mine fossils and resurrect ancient creatures to fight for them. At the same time the player is foiling this, they have set up shop in both Celadon and Saffron City, and are up to no good in Lavender Town. The side-arc actually gets kind of complex here, and kids will blow through it busy leveling up their Wartortle or Charmelion (no one players an Ivysaur, be real), and worried about catching Onix. But I am not a kid. I am an adult, playing a Pokémon game, on my summer vacation, and then spending time writing hundreds of words about--OH NEVERMIND, just.... *sigh*
In Lavander Town, Team Rocket is working on capturing GHOST Pokémon creatures because the gang is so powerful. In doing so, they have killed a Marowak, and orphaned its Cubone baby. The Marowak's soul haunts them and holds them back, until the player can arrive. That is grim. It is even worse when you realize that Rocket is working on stealing the souls of people's dead pets in a looming crypt tower, while people mourn their pets on the levels below. Actually, this whole thing has been explained before, so check out this video for a great analysis:
The problem with the Lavender Town plan is that they cannot see or identify the ghosts. They need a SILPH scope, and so does the player. In the meantime, Rocket has also set up shop in Celadon City, where they have become racketeers, literally selling the creatures captured in their other schemes as payouts for casino patrons. Yeah, the player, should you choose to engage the NPCs in the casinos, can learn a bit about addiction. It is funny, but also sad. Pushed by the plot, the player infiltrates the Rocket base below the casino, defeats Giovanni, and obtains a SILPH scope, enabling him to fight off the ghosts in Lavender Town, and put the soul of Marowak to rest--and drive Team Rocket from the tower. There is a run-in with the Rival here, and his careless handling of the situation, versus the energy the player invests in solving it, again highlights the difference between them. But the Rival is not the problem: Team Rocket is.
These plans foiled, Rocket shifts focus to Saffron City, where they are plying the skyscraper HQ of SILPH Co. for more technology to help them. They player must chase them out of this area as well, and in doing so earns a master ball, which can be used later to capture an abomination of Team Rocket experimentation. (I should note an interesting side-theory: all of the steps Team Rocket is taking result in obtaining a master ball; some players have theorized that this was Giovanni's main end, not obtaining the technology but the item itself, in order to capture MewTwo, perhaps in an anti-heroic gambit to save the world from a dangerous beast. But who knows?)
That is a lot of twisting, turning content packed into the middle of the game, and easily overlooked by just mashing A and going through the motions of moving from trainer battle to trainer battle. I label this stuff side-quest because the player's main objective is not to clear Lavender Town of Rocket gangsters, but to obtain the pokéflute to move Snorlax's corpulence off the road and allow transit to Fuchsia Town, and to clear Saffron so you can fight the city's gym leader. They are compulsory actions, but the plot is buried in speaking to NPCs, mostly.
There are other strange side-plots, as well; Pokémon's Gen. 1 games do a great job of environmental storytelling in ways that one might not be used to thinking about. Environmental storytelling is often pointed out in games like Bioshock, or Borderlands. But I ask you: where are all the adults at the Power Plant east of Cerulean? Why is the Saffron Fighting Gym not a real Gym? What happened at the Cinnabar Island Pokémon Laboratory between Dr. Fuji, Blaine, Mew, and Mewtwo? How is Lieutenant Surge an American soldier in a fictional world? Largely, the game pulls this trick by not directing your attention to these things. It might set up a dungeon or state some NPC dialogue, and leave it at that. A child's developmental state is a lot different from an adult's thought, and so what a younger player will take at face value, an adult can find an interesting omission, and that is largely how I experienced Pokémon Blue, returning to play it after a ten year gap. There is a lot of story that is untold yet still experienced, despite--or perhaps through--very simplistic art, mechanics, and music. Twenty-odd years later, I still found myself surprised a few times, especially as I paired what narrative the game hands out with what snippets the Pokédex gives you.
OVERALL REACTIONIs Pokémon (Gen. 1) Lit? Well, no. The main story is really not engaging at all. I could not care less whether my player got the next badge or beat the Elite Four, except insofar as it allowed me to use new powers for the sake of further collection. But there are enough seeds sewn that it definitely has value as a popcorn narrative. In my 35+ hour play through of Blue over the last few weeks, I collected 90+ critters and beat the game, including the Elite Four, and exploring Cerulean Cave. I did not get very invested in the narrative, and since one critter is essentially the same as another (unlike other JRPGs, where team members have personality or dialogue options), I did not grow very invested in my party except to min/max efficacy for the sake of battling and collecting.
Some of the side-plots and environments definitely tickled my fancy. It got me to write this post, after all. Unfortunately, Gen. 1 does not deliberately ask or answer any of the interesting questions it implies. That might be for the better--a specific answer can definitely age, and poorly so. But that may also be a limit of technology. I am aware that the games have been remade in recent years, and I am curious to see how or if Kanto's kleptomaniac dream has tarnished with more detail. As of the original Blue, bought and played on my 2DS, it is more of a come-for-the-mechanics affair.
But we knew that going in, right? Pokémon is not a game you recommend on the merit of its narrative. Pokémon is an experience, the phantom-itch of collecting them all, of exploring a weird world with its weirder creatures, and occasionally fighting off the greedy, evil gangsters who want to ruin that for their own short term gain.