IMPORTANT: Previous Generations FAQ: Help Wanted

Generation 1 takes place in the Kanto region. In Kanto, players may choose between the following three Pokemon: Charmander, Squirtle and Bulbasaur. Which one you pick is ultimately up to you but I'll try and break it down as best as I can. Whichever one you choose, your rival will choose the one that best counters yours so choose wisely! For those who play Pokemon Yellow, you get Pikachu by default while your rival gets Eevee. If you want tips on how to use Pikachu, see below. But first... the Kanto starters.


Charmander
Veterans of Generation 1 consider Charmander to be the "Expert" option for a starter. Charmander is a Fire Type Pokemon. Fire Types are typically fast and very powerful when it comes to its Offensive capabilities. Defensively speaking though, they're a bit lacking. It doesn't mean Charmander is a bad Pokemon. You just have to put it in situations where it will shine the brightest. It learns Slash(a strong physical move that Critically hits often), Flamethrower(Best and most reliable Fire Type move there is) and Fire Spin(Fire Type move that when it hits traps and locks down the opponent).

The reason Charmander is considered an "Expert" Pokemon is due to two factors. First factor is that Fire Types counter Grass, Bug and Ice Types. The first two are few and far between and don't appear often(exception being Erika's Celadon Gym) while the final Type in Ice is often paired with Pokemon who have Water Typing(the exception being Jynx). This makes them resistant to Fire Type attacks while at the same time having a Super Effective counter to your Fire Type starter. The second reason is the first two Gym Leaders: Brock and Misty. Charmander will struggle against Brock's Rock Type Pokemon since they resist both Fire and Normal Type moves. Try to catch a Caterpie(from which you will evolve into a Butterfree) and Butterfree's Confusion should make short work of his Rock Type Pokemon(who have a weakness to Special attacks such as Confusion). Against Misty's Water Pokemon, Charmander is at a complete disadvantage. Fortunately, you have three means of countering her. You can catch a Pikachu in Viridian Forest, catch a Paras(a Bug/Grass Type) at Mount Moon, or catch one of the version exclusive Grass Types north of Cerulean(Red its Oddish, Blue its Bellsprout). After that, Charmander can effectively fight every Gym Leader from that point onward.

Charmander evolves into Charmeleon at level 16 and Charizard at level 36. Additionally, Charmander's final Evolution in Charizard gives it Flying Typing. This addition makes him invulnerable to Ground Type moves that otherwise would have been Super Effective. As a consequence though, he now becomes vulnerable to Electric, Rock and Ice Type attacks. Whats worse is that in Red/Blue version, Charizard can't learn any Flying Type moves(like Fly) to take advantage of his new wings(Yellow Version he can). Even so, Charizard is a solid Pokemon and a worthy starter.

For a Charizard moveset, I advise the following:

Slash: Although its not the strongest Physical move there is, the fact it critically hits so often is why its here. You'll be surprised just how powerful this move is on Sabrina's Psychic Pokemon and it learns this move naturally at level 30 provided you don't evolve it right away into a Charmeleon. If you do it learns it at level 33.
Flamethrower: Arguably the best Fire Type move in the game. Charmander learns it naturally at level 38 while it takes Charmeleon until level 42 and Charizard until level 46. Keep this in mind when it comes to evolving your starter.
Earthquake: Best Ground Type move in the game that also helps against Rock and Electric Pokemon who otherwise would cause a problem for you. Also is Super Effective against Poison Types. You find this move in the form of TM26 that's located in Silph HQ in Saffron City.
Double Team: An Evasion move that when used right can allow your Fire Starter to sweep entire teams solo. Not a guarantee to prevent you from taking damage but it certainly helps a lot. It can be found in Celadon's PokeMart or in Fuchsia City as TM32.


Squirtle

Squirtle is a Water Type Pokemon and is a Turtle Pokemon. Being a Turtle, its speed is the slowest of the three starters but it makes up for it by having the strongest Defense of the three. Despite being slow, it has a solid start by being Super Effective against Brock's Rock Types and resistant to Misty's Water Types. Just be aware that against Lt.Surge, Squirtle is a sitting duck. Same deal with Erika(even if it knows an Ice Type move) but otherwise Squirtle is awesome against everyone else. Its movepool is diverse and it includes being able to learn moves that counter Pokemon who otherwise would have an edge on it. Squirtle evolves into Wartortle at level 16 and Blastoise at level 36.

Suggestions for a Blastoise moveset:
Strength: Although its an HM move, its a STRONG Physical move that gives Blastoise a means of fighting Pokemon it otherwise couldn't effectively(like Water Types). HM04 is obtained in Fuchsia City.
Ice Beam: Ice Beam is a strong Ice Type attack that gives Blastoise a counter against Ground, Flying and Dragon. Obtained at top of Celadon PokeMart.
Surf: Another HM move that also gains STAB. Completely obliterates Fire, Rock and Ground Pokemon. Obtained in Fuchsia City.
Earthquake: Taught via TM26, this move gives you a counter against Electric and Poison Type Pokemon while also acting as another strong Physical move.


Bulbasaur

If Charmander is considered to be the "Expert" Pokemon, Bulbasaur is the "Novice" Pokemon. Namely, if you're new to Pokemon or Red/Blue, Bulbasaur should be your choice. Bulbasaur is Super Effective against Brock and Misty while resisting the next three Gyms! Although its marginally faster than Blastoise, its stats are relatively balanced. Its movepool is also solid while being able to abuse several Generation 1 perks. You can find out about those perks later on in the FAQ. Be sure to level Bulbasaur to level 13 prior to facing Brock so that you have Vine Whip at your disposal. It evolves into Ivysaur at level 16 and Venusaur at level 32. That's earlier than the other starters, which is another bonus.

Suggested moveset for Venusaur:
Cut: Most Grass Type Pokemon get relegated to this mandatory HM move(Namely SOMEONE has to learn it). It deals solid physical damage and honestly gives Venusaur a means of effectively fighting Pokemon it otherwise couldn't(like Grass and Poison Types). IF you find someone else to learn Cut, a solid alternative is the move Growth.
Razor Leaf: Due to its above average rate of obtaining Critical Hits, this is a signature move of the Bulbasaur line as I see it. If bolstered by the move Growth, Razor Leaf can easily OHKO just about anyone. It naturally learns this move at level 27 as a Bulbasaur but also at level 29 as an Ivysaur.
Leech Seed: One of the first moves Bulbasaur learns is this handy dandy Grass Type move. It slowly drains HP from the target Pokemon and gives it to Bulbasaur. This move can tip the scales into your favor.
Toxic: This is a move you obtain from Koga after defeating him in the Fuchsia Gym. It badly poisons the target such that they take more and more damage the longer the battle goes on. Toxic is best paired with Leech Seed(see Perks Question for explanation).


Pikachu
Pikachu is the Yellow Version Exclusive starter. You may be thinking to yourself... I don't want an Electric Mouse, I want one of the Kanto starters. What the hell is Pikachu going to do against Brock when its Electric Attacks aren't even effective against it? At least Charmander's Ember does damage. While that is indeed true, Yellow version gives you three particular perks.

Firstly, Pikachu has a special attack in the form of Thundershock from the beginning. Kanto starters have to hit level 8 before they even learn their first Fire, Grass or Water Type move(and Bulbasaur's first Grass Type move is Leech Seed. Doesn't learn Vine Whip until level 13!!!). Pikachu's Thundershock makes him a god against the early route Flying Types, hence can level up relatively fast because of this.

Secondly, Pikachu's moveset has it learning Double Team at level 15(a move it doesn't learn at all in Red/Blue). Use of Double Team all but makes Pikachu impervious to attack and in combination with Tail Whip and Quick Attack, Pikachu can single handedly take Brock down. It also learns Thunderbolt naturally at level 26(Red/Blue Pikachu's and other Electric Pokemon.... eat your heart out).

Lastly, if you don't like the thought of facing Brock with your Electric starter, fear not for the game exclusively gives you three options. Option #1: Butterfree. Tried and true classic from Red/Blue that also works here. Option#2: Mankey. Unlike in Red/Blue, Mankey learns Low Kick at level 9. Low Kick is a Super Effective Fighting Type move that is more than enough for Brock's Rock Type Pokemon. Option#3: Nidoran(Male OR Female). Nidoran line in Yellow Version learn Double Kick at level 12. Double Kick is a Fighting Type move that is Super Effective against Brock's Rock Type Pokemon. In Red/Blue, Male Nidoran don't even learn the move and Female Nidoran don't learn it until level 43(way too late to be viable).

Honestly, there is no right answer to this question because we each have our own personal preference as to what Pokemon we love and hate. Before answering this question, we must first note what Pokemon are unavailable to us. The following Pokemon can not be caught normally in each respective version:

Unavailable in Red:
Sandshrew
Sandslash
Bellsprout
Weepinbell
Victreebel
Meowth
Persian
Vulpix
Ninetales
Pinsir
Magmar
Mew

Unavailable in Blue:
Ekans
Arbok
Oddish
Gloom
Vileplume
Mankey
Primeape
Growlithe
Arcanine
Scyther
Electabuzz
Mew

Unavailable in Yellow:
Weedle
Kakuna
Beedrill
Ekans
Arbok
Meowth
Persian
Koffing
Weezing
Raichu
Jynx
Electabuzz
Magmar
Mew

Now having noted what Pokemon are available to you, what you catch is largely determined by two factors: Your starter and what challenges/Gyms you have left to face. I'll break it down by starter.

If Charmander is chosen:
Charmander early on is going to rely heavily on the Pokemon you catch due to its ineffectiveness against the first two Gym Leaders. Highly recommend you catch two or three Pokemon prior to facing Brock. The first Pokemon you'll want to get is a....


Pikachu

Pikachu in Red/Blue serves two immediate purposes. 1) It counters the early-game flying type Pokemon, including your rival's Pidgey/Pidgeotto/Pidgeot. 2) It zaps the living crap out of Water Type Pokemon, including Misty's, Lorelei's Water/Ice Types, Lance's Gyrados and your rival's Squirtle/Wartortle/Blastoise. You will definitely want to teach it Thunderbolt and evolve it into Raichu around level 50 or so.

Up next...

Butterfree

Butterfree is an early game Bug Type that evolves from a Caterpie. Its more prevalent in Blue Version than it is in Red but this Butterfly Pokemon will easily beat Brock for you thanks to its Confusion Attack. It also can serve you later on in the game against Erika's Grass Pokemon(since two have Poison Typing) and Koga's Posion Type Pokemon through its Psychic Attacks. Just watch out for Poison moves as Poison does a number on Butterfree due to its Bug Typing.

Third option and one that is frankly optional is....

Pidgey

Pidgey is useful early on due to its Sand Attack. Moves that decrease Accuracy are invaluable in Generation 1 and are often overlooked or underutilized. Through the use of Sand Attack, Pidgey alone can defeat Brock or any Pokemon who's attacks have average to below average accuracy. The reason I consider Pidgey optional is due to other Flying Types(Spearow or Doduo) and the fact Butterfree does a far better job in the early game.

Other Pokemon to consider later on....


Gyrados

You get a Magikarp from a salesman. Takes a long time to train but once you get one... it can be the MVP of your playthrough. Strong Physical Attacker that can also dish out Water if taught attacks(doesn't learn any Water moves until level 41).


Bellsprout *Blue Exclusive*

Cut HM candidate that can be an asset against Misty, Lt.Surge and any future Rock, Ground and Water engagements. As a Bellsprout, it learns Razor Leaf at level 33.


Oddish *Red Exclusive*

Cut HM candidate that can help against Misty, Lt.Surge and any future Rock, Ground and Water engagements. Signature move is Petal Dance(just prepare for its side-effect).


Abra

Abra line is one of the best Pokemon lines in the game. Although weak to Physical moves, its speed and special attributes are frankly second to only Legendaries(Mew/Mewtwo). Furthermore, Psychic Pokemon are impervious to Ghost Type Pokemon, hence Pokemon Tower and Agatha in the Elite 4 will be a cake walk.


Doduo

Solid Flying Type that despite being a wingless bird can learn Fly. Glass Cannon like stats with speed and physical offensive firepower that is hard to ignore.


Spearow

Spearow line is an early game Flying Type that frankly is better than Pidgey Line from a Flying Type perspective. It learns Drill Peck and is an alternative to Doduo line.


Farfetch'd

You get this Pokemon via a Trade and while its stats leave much to be desired, it's what it can learn that justifies mentioning it. It naturally learns Swords Dance, a move that drastically increases Attack Stat. In combination with Double Team(that bolsters your Evasion and would give you the time to use Swords Dance), you can then use Slash(which has a higher critical hit ratio) and other physical type moves to unleash a lot of damage on opposing Pokemon. It also can learn Cut, hence makes for a great HM Pokemon.


Lapras

You're practically given this Pokemon for free and being that you've started with Charmander, this is the PERFECT Water/Ice Type Pokemon. A bit slow but Lapras is Lorelei's Ace for a reason.


Snorlax

Unlikely to ever go before your opponent due to Snorlax's speed but its sheer HP and knowing the move Rest makes that flaw virtually moot. Tack on Amnesia for boosting Special stat(which is useful against Special Attack users), Hyper Beam(which gains STAB) and Body Slam(which also gains STAB and can paralyze) turns it into a pretty strong Physical powerhouse.

If not Snorlax, then also consider...


Tauros

Its speed and its ability to learn a wide variety of moves makes this Pokemon extremely useful.


Dratini

Harder than most Pokemon to catch due to exclusively being in the Safari Zone, the fact it evolves into Dragonite is why I'm mentioning it.

If Squirtle is chosen:

Early on, you can get by without needing too many Pokemon to aid you. About all you will really need is a counter to your rival's Bulbasaur. Hence I recommend catching at least two Pokemon early on.


Pikachu

Pikachu is worthwhile for two reasons. 1) Zaps early route Flying Types, including your rival's Pidgey/Pidgeotto/Pidgeot and 2) Zaps Misty's Water Type Pokemon and your rival's Gyrados(heck throw Lorelei and Lance in while we're at it).


Spearow

Spearow gives you an early game Flying Type with Flying Type moves(which is what separates it from Pidgey). These Flying Type moves can be used to defeat your rival's Bulbasaur until you get your hands on a Fire Type.

Other Pokemon to consider:


Vulpix *Blue Exclusive*

Vulpix is my favorite Fire Type and is exclusive to Blue version(Red players need not apply). Learns Flamethrower incredibly early(level 35) and has the added bonus of knowing Confuse Ray(a move I hate getting hit with).


Growlithe *Red Exclusive*

Growlithe is the Red Exclusive Fire Type with an Evolution that puts it into Quasi-Legendary status. If there is any downside to this Fire Type Pokemon is that it doesn't learn Flamethrower until level 50 and by being in the SLOW XP group, this is a real turn-off.


Magmar *Blue Exclusive*

Magmar was made famous by the Pokemon Anime as Blaine had used one to fight Ash's Charizard. Problem is that you'll catch one too late to be of any real use besides Lorelei's Jynx and your rival's Exeggutor. While it does learn Fire Punch at level 43(not long after catching it at level 38), it doesn't learn Flamethrower until level 55.


Sandshrew *Blue Exclusive*

Being that you have a Water starter, you're going to want a Ground Type Pokemon for Lt.Surge and I find Sandshrew line to be one of the best ones. If there is any flaw about the line though is that it doesn't learn any Ground moves naturally. While that is indeed a bummer, it learns Slash, Sand Attack and Swift. Teach it Dig and it will serve you for the rest of the game.


Diglett

Diglett is for those on Red Version and while I indeed prefer Sandshrew, Diglett is not without merit. Its fast and pretty strong offensively. The reason I prefer Sandshrew though is that its defenses and hitpoints leave much to be desired.


Abra

Hard to ignore Psychic types. Makes beating Agatha in the Elite 4 so much easier.


Dratini

Not entirely necessary based on the Pokemon I've already mentioned but if you're willing to train/evolve it, its a true powerhouse.


Oddish *Red Exclusive*

Solid candidate for Cut and a Pokemon that can help against Misty and future Rock, Ground and Water engagements. Although slower than Bulbasaur and Bellsprout lines, it has the unique Petal Dance attack(just prepare for its inevitable side-effect).


Bellsprout *Blue Exclusive*

Like with Oddish on Red, Bellsprout is a good candidate for Cut on Blue version. Faster than the Oddish line and learns Razor Leaf at level 33.

If Bulbasaur is chosen:
Bulbasaur is known as the "Novice" starter for a reason. You can pretty much fight the first five Gyms if you wanted to. However, you're going to want back-up and a counter to your rival's Charmander. As such I recommend capturing the following Pokemon:


Pikachu

I've been recommending Pikachu for the other starters and this time is no exception. While Pikachu is not necessarily needed for Gym Leaders, it will help cover Bulbasaur's weakness to Flying Types, including your rival's Pidgey/Pidgeotto/Pidgeot.


Magikarp

I'm not recommending using Magikarp in its base form but what it evolves into....


Gyrados

Training Magikarp is going to take time and patience since its in the Slow XP group but once it evolves into Gyrados, you'll want to teach it Water Gun via TM(found in Mount Moon) to give you a solid Water Pokemon that can serve two roles: Strong Physical Attacker(which it naturally does anyway if given a strong moveset, including learning Hyper Beam naturally at level 52) but also can counter your rival's Fire Type starter with strong Water and Ice Attacks(via teaching it Ice Beam). Its Flying Typing also makes it impervious to Ground Type moves, hence Giovanni is at your mercy(for Red/Blue version. Yellow Version is not so easy).


Lapras

You can utilize not one but two Water Pokemon by having Gyrados specialize as a Physical Attacker and Lapras as your Water/Ice specialist. Only reason I bring up Gyrados prior to Lapras is that you'll have done all but two of your rival battles by the time you acquire it at level 15.


Geodude

If Gyrados doesn't fancy you, then Geodude can more than do the job since Brock gives Charmander users nightmares(especially on Fire Red/Leaf Green). Learns Earthquake naturally at level 31.


Abra

Feel like a broken record but Psychic Types are strong for a reason in Generation 1. Counters Fighting, Poison and Ghost Pokemon with ease.

If Pikachu was chosen:

With Pikachu as your starter, you have the options I mentioned in the previous question. Of the those I recommend you go with the following:


Mankey

Not only does Mankey do Super Effective moves on Brock's Rock Type Pokemon, it also destroy's your rivals Eevee while its still in its base form. When he evolves it, your Mankey loses alot of its appeal in the late game. Early on though, Mankey is extremely useful, particularly against all those Youngsters with Rattata's.

If you don't like Fighting Pokemon or want a different option, then I'd go with...

Butterfree

Not only can it handle Brock's Rock Pokemon but it can serve a purpose later on against Ghost Pokemon with its Psychic attacks.


Sandshrew

Virtually guarantees a victory against Lt.Surge and against your rival(who typically evolves his Eevee into Jolteon provided you beat him twice or Flareon if only once. RARELY will you get the opportunity to have him evolve it into Vaporeon that requires you lose the opening bout and either skip/lose the 2nd fight off Route 22).


Charmander

Bulbasaur

Squirtle

You can acquire all 3 Kanto starters in Pokemon Yellow. I mean if they're there for the taking, why not use them no? If you don't want to use Kanto starters, that's fine.

Alternatives....


Vulpix

Solid Fire Pokemon


Lapras

By the time you'll need a Water Pokemon, this one, with training, will exceed expectations.

Pokemon that can be used in all versions:


Clefairy

Surprisingly this Normal Type Pokemon can dish out some real punishment with the right moveset. Give it Surf and other Special oriented moves and this cute and fluffy Pokemon(before Stitch came along) will surprise even the most battle hardened veterans.


Staryu

Its not so much its base form that is of interest but more so its evolved form in Starmie wherein it gains Psychic Typing. Give it the move Psychic to go along with Surf and you'll find that this Water Type Pokemon can fill a niche role within your party.


Slowpoke

Its obvious that when a Pokemon has "slow" in its name, its slow. Speed not withstanding, this Pokemon can be scary good if set-up. Lorelei has one in her team on Yellow and its a scary Pokemon to behold if you don't knock it out fast. It naturally learns Amnesia and Psychic. Give it Surf(like it knows on Yellow version) and another move like Rest or Double Team and watch it melt opponents if allowed to power up.

The answer to this can be found in the following link: Generation 1 misinformation but the TLDR answer is that Damage is correctly applied but due to the target Pokemon's Dual Typing(Poison/Ground), what is displayed is determined by what appears last in the list. Since Grass vs Poison is slotted behind Grass vs. Ground, it returns a NVE result even though the game applied normal damage(Grass is x1/2 vs. Poison but x2 vs Ground for a x1 result). The list I linked is displayed in reverse order to show what the game will return.

Typing in Generation 1 is nothing like that of future games. Not only has GameFreak(maker of Pokemon Games) added Steel, Dark and Fairy Types to the Games but the Typing of Pokemon and moves themselves have changed. Specifically with regards to Generation 1 and the question at hand, Ghost moves such as Lick and Night Shade have no effect on Psychic types. See the Type chart(which you can see here: Type Chart) for more. Therefore when venturing into Pokemon Tower in Lavendar Town and facing Agatha of the Elite Four, it's advised to have a Psychic Type Pokemon in your arsenal.

Kanto region has 8 Gym Leaders. They are as follows:

Pewter City Gym Leader: Brock
Cerulean City Gym Leader: Misty
Vermilion City Gym Leader: Lt.Surge
Celadon City Gym Leader: Erika
Fuchsia City Gym Leader: Koga
Saffron City Gym Leader: Sabrina
Cinnabar Island Gym Leader: Blaine
Viridian City Gym Leader: Giovanni

Brock specializes in Rock Type Pokemon, hence Fighting, Grass and Water Types will have an easy time against him. Misty uses Water Types so use Grass or Electric to spoil her day. Lt.Surge specializes in Electric so any Pokemon with Ground Typing should be utilized. Erika is a Grass Type expert, hence Fire, Flying and Bugs really hurt her. Psychic also works due to two of them having Poison Typing. Koga is a Poison Master so Ground and Psychic really prove invaluable against him. Sabrina uses Psychic Pokemon and their only true weakness is to Bug Types or any Pokemon with a Strong Physical Attack(like Slash or Body Slam for example). Blaine uses Fire Types so Water and Ground can put out the flames. Finally Giovanni uses Ground so Water is typically the best option due to some of his Pokemon having a Resistance to Grass. Flying is another possibility due to its invulnerability to Ground Type moves.

Aside from the Pokemon available and where they appear, there are several differences. The first notable one is that your starter is always Pikachu on Yellow version while your rival always gets Eevee(On Red/Blue, you pick from one of three Pokemon and your rival picks the one that can easily defeat yours). Now while you're locked into having Pikachu, Yellow version was kind of modeled after the Anime. Namely Jessie and James of Team Rocket make several appearances along with their Ekans, Koffing and Meowth. Furthermore, you're able to acquire all three Kanto starters just like Ash.

However, the biggest glaring difference is in the Gym Leaders and Elite Four. Their teams are sometimes drastically different, much higher in level and have a far different moveset than their Red/Blue counterparts. In Yellow, Brock's Pokemon are two levels lower and his Geodude doesn't know Defense Curl. This allows a player using Pikachu or another Pokemon with a Defense lowering move like Tail Whip to drastically lower his Defense and beat him with Pokemon that might otherwise have a difficult time(like Pikachu and that's despite the Yellow version exclusive options as well). Misty's Pokemon remain unchanged but Lt.Surge has his entire team replaced with a single Raichu(just like the Anime) at level 28(much higher than 24 and with a different moveset that isn't completely reliant on Electric moves. It knows Mega Punch and Mega Kick, hence it can fight even Ground Type Pokemon if it's not taken out ASAP). Erika's Team is much higher in level wherein she opens with Tangela at level 30. Then Weepinbell at level 32 that is followed by her Ace in Gloom at the same level(again just like the Anime).

Koga's Team is completely redone for Yellow. If you'll recall from the Anime, they're noted for using the Venonat line, hence his entire team consists of that and it's evolved form of Venomoth. However, instead of being in the mid 30's to low 40's, his Pokemon start at level 44 and increase by increments of 2 to 50! Not only are his Pokemon much stronger but they all know Psychic and carry his signature Toxic move. His Venomoth is particularly nasty due to also knowing Double Team. Sabrina also got an overhaul as her team consists entirely of the Abra line at level 50. Fortunately, her starting Abra is her weak spot since it knows only Flash and Teleport so exploit it! Blaine's Pokemon Team has shrunk from 4 in Red/Blue to 3 in Yellow. While you have fewer opponents, they're all much higher in level with his Arcanine being level 54! Giovanni's Team is much stronger and better equipped in my opinion as his Pokemon's Moves are able to counter Pokemon that might otherwise cause him troubke(like Water and Flying Types). He also has a Persian that knows Double Team, hence can ruin your day if it's allowed to use it.

The Elite Four are also more competent with better movesets in Yellow version. Lorelei's Slowbro is scary when it has Amnesia to boost Surf and Psychic(two strong STAB moves). Bruno's Hitmonchan and Hitmonlee both know Double Team. Agatha's first Gengar knows Mega Drain and her last one knows Psychic instead of Toxic(which was moved to her Golbat). Lance also got upgraded with his first Dragonair knowing Thunder Wave and Thunderbolt to counter Water Pokemon who may know Ice Type moves.

Your rival also got changed a bit. In Red/Blue, his team is based largely on what starter you picked. See Red/Blue rival for more detailed info. For Yellow, what team he ultimately gets is dependent on the following two outcomes: First rival battle and Route 22(2nd rival battle). If you win both: Jolteon. Win first but lose/skip 2nd(or lose first, win 2nd): Flareon. Lose first and lose/skip 2nd: Vaporeon. See Yellow Rival for more detailed info.

Surprisingly, Generation 1 is chock full of them. I won't list them all as they can be easily found with a bit of searching on the Internet but I'll list the four most glaring ones that come to mind.

Perk/Exploit#1: Toxic
A detailed explanation of the move can be found here: Toxic explained You obtain Toxic from Koga and this move must be given to a Pokemon with Leech Seed. Why you ask? It's because Toxic and Leech Seed use the same algorithm when calculating damage which is N(which starts at 1) * x(which is 1/16th of Target Pokemon's Max HP). When a Pokemon is afflicted with Toxic and takes Poison Damage from Toxic or damage from Leech Seed, N increases by 1. That means N can be increased by 2 every turn if both are utilized and the amount of damage both do(and life recovered from Leech Seed) is drastically increased. Even if the Poison is removed via a Pokemon using Rest, the N counter is not reset and can still be increased if the affected Pokemon is hit with Burn Damage and Leech Seed Damage. In other words, Toxic is Leech Seed's best friend and then some and turns it into what would have been an afterthought move to one that is godly against pretty much ANYTHING but Poison Types(since they can't be Poisoned to start with). N is only reset if Toxic is used to badly Poison the target again. This is why Bulbasaur is the King of Kanto starters since it's one of two Kanto Pokemon who can learn Leech Seed(the other being Exeggcute at level 28).

Perk/Exploit#2: Ditto Glitch
For a detailed explanation see this.

The following glitch takes advantage of the following list: Hexidecimal list. From this list, you can force an encounter with any Pokemon you want, including Legendary Pokemon Mew and Mewtwo. This Glitch enables you to complete your Pokédex without trading. While the glitch could be called the "Hexidecimal list glitch", it's more apt to call it the "Ditto Glitch" since you will be using Wild Ditto to carry it out. Red/Blue users have an easier time since Wild Ditto appear earlier while Yellow users have to go to the Cinnabar Mansion basement to find Wild Ditto.

The first thing you do is the Trainer-Fly glitch. To carry it out, you find a LDT(Long Distance Trainer or a Trainer that activates at any point in their line of sight). The best LDT is the one left of Nugget Bridge. You will want to walk until your just off screen. Before proceeding further, save the game so if you mess up you can start over. Then move down into the LDT's sight but press start to open the menu prior to the Trainer appearing on screen(takes a bit of practice). Should you successfully open the menu prior to the Trainer giving !, Fly to an area with a Trainer you've yet to battle. Have that trainer see you and have them walk at least one space to battle you(game locks up if you don't have them walk). Upon defeating the Trainer, Fly to where you run into Wild Ditto. When trying to encounter a Ditto, have the Pokemon you want Ditto to transform into at position 2-6 in your team list or not first. That way when you switch it in, Ditto transforms into that Pokemon. Once you get Ditto to transform and copy the "Special" stat of the last Pokemon encountered, you will want to run from battle or defeat it(running is quicker). Then fly back to Cerulean City. For Yellow version users, since you're in mansion basement, it's advised having a Pokemon with Dig/Teleport or an Escape Rope so you can exit without encountering another Pokemon. Once you're in Cerulean City, walk towards Nugget Bridge. Menu will then open on its own(a sign that the glitch worked). Press B to close the menu to initiate a Wild Pokemon encounter. What Pokemon you face is based on the Special stat of the Pokemon Ditto copied. The Special stat corresponds to that Hexidecimal list so if you had Ditto copy a Pokemon with a Special stat of 30, you will battle Tangela.

The reason we use DItto is because we never know what special value Trainer Pokemon have. If you know what special value a Pokemon Trainer's Pokemon has, then you have "special" cases wherein you can skip the Ditto step altogether. An example of this is the "Mew" Glitch or a special case of the Ditto Glitch. The Slowpoke Trainer north of Cerulean City has a level 17 Slowpoke with a special stat of 21. If you pull the Fly-Trainer Glitch with the LTD Trainer I noted above, Fly back to Cerulean and then fight the Slowpoke Trainer, you'll get the encounter with Mew the next time you travel towards Nugget Bridge. Neat Exploit no? Also, this glitch can also be used to duplicate items like Rare candies and Master Balls. To duplicate items, you'll want Ditto to transform into a Pokemon with a Special stat of 182-184. These special values are stable and you'll want the item you want duplicated in the 6th slot on your item list. Once you encounter the "stable" Pokemon listed in the Hexidemical list, the 6th item in your list will be multiplied considerably.

Perk/Exploit#3: Special stat
In Generation 1, a Pokemon's Special Attack and Special Defense are lopped together into one value. In Generation 2 onward, Special was split into Special Attack and Special Defense. Why is Special being a single value in Generation 1 so important? It's because any Pokemon who can raise its Special(like Snorlax or Slowpoke with Amnesia and Bulbasaur/Bellsprout with Growth) raises both Special Attack AND Special Defense at the same time. This makes them more resistant to such moves while boosting their own Special attacks. Bulbasaur is again the biggest benefactor of this because it's Razor Leaf is not only STAB(SameTypeAttackBonus) but is a Special Attack with a higher Critical Hit ratio.

Perk/Exploit#4: Focus Energy and Dire Hit
More of a bug than an Exploit, Pokemon who use the move Focus Energy or are affected by the item Dire Hit are adversely affected. Namely instead of increasing their Critical Hit Chance by a factor of four, it's instead reduced by the same factor.