Original article:
Important RBY Differences
Pokémon versions Red/Blue/Yellow stand out for being some of the glitchiest video games ever made. However, in my opinion, it is what creates the RBY charm. Many things work differently in RBY than they do in the later generations where most of the glitches have been fixed.
This is a list of everything that works differently in RBY.
Important Differences
Special Stat
Instead of being divided in Special Attack & Special Defense like in GSC or RSFRLGE, there is only one Special Stat in RBY. It covers both Special Attack and Special Defense. Every move that raises or drops the Special Stat, such as Amnesia or Psychic, will therefore affect the Pokémon�s ability to both use special attacks and take special hits. In GSC, every Pokémon was given their Special split. They all, however, kept their original Special Stat value for either Special Attack or Special Defense. While they managed to tone down several Pokémon that were overpowered (ex: Alakazam) and make some others better (ex: Hitmonlee), they also weakened some that werent especially strong (ex: Tangela) and made some that were already strong ever better (ex: Snorlax).
Critical Hits
In RBY the Critical Hit Ratio is based on Base Speed rather than having a set Ratio. Which means that, yes, faster Pokémon will Critical Hit more than slower ones. This is very important to consider in RBY as most of the faster Pokémon will have a Critical Hit ratio higher than 20%. The Ratio, being based on BASE speed, will not change if the Pokémon is paralyzed or suffers a speed drop.
Formula to calculate a Pokémon's CH ratio : CH%=BaseSpeed*100/512.
In addition, when moves Critical Hit, they will ignore any stat change you and your opponent might have, beneficial or otherwise. For example, if you used Amnesia 3 times to maximize your Special stat and then score a Critical Hit, you will actually do less damage than you would have if you didn�t, only doing twice as much as you would normally do without boosts. Critical Hits will also ignore Reflect and Light Screen.
High Critical Hit Moves
Razor Leaf, Slash, Crabhammer, and Karate Chop. Like normal Critical Hits they are also based on Base Speed and the formula used for those mean they nearly always give a Critical Hit.
The CH ratio formula for High Critical Moves in RBY is : CH%=BaseSpeed*100/64.
Freezes
There is only two ways to unfreeze, and those are either by getting hit by a Fire type attack or if your opponent uses Haze while your frozen Pokémon is in play. The frozen Pokémon will never thaw by itself.
One-Hit KO Attacks
Based on Speed, but not on Base Speed. The attack will always fail if you are slower than your opponent. It may only succeed if you are faster or have the same speed.
Trapping Moves
Wrap, Fire Spin, Clamp, and Bind. Instead of preventing switching they prevent your opponent from attacking after it hits during the whole 2-5 turns the attack may last. So, if you are faster than your opponent, you can keep using Wrap over and over again and they cannot hit you back. Only the first hit of the 2-5 attack sequence wastes a PP and is subject to miss due to accuracy. The wrapping Pokémon isn't allowed to use any other attack until the 2-5 turn sequence ends. In addition, a Critical Hit is only also calculated for the first hit, if it does score a Critical Hit, every remaining sequence hit will do that amount of damage. Using a wrapping move can also be used to get a free switch. For example: Cloyster uses Clamp on an incoming Starmie. Cloyster can switch out freely the turn after while Starmie will stay immobilized for that turn, but will still be released from the Clamp. The pokemon will also remain immobilized if the user of the partial trapping technique is fully paralysed mid sequence but the sequence will end.
If a wrapped Pokémon switches out while in the middle of a wrap sequence, the sequence resets and the accuracy must be tested again on the switch and another PP is wasted. If at such a time the trapping move has 0 PP, it will still be used against the incoming pok�mon. After that use, the current PP of the trapping move will roll over to 63.
If the target of the partial trapping move just used Hyper Beam, it won't have to recharge if the partial trapping move misses on the recharge turn. Additionally, if the user of the partial trapping move attacks before the user of Hyper Beam during a recharge turn and the partial trapping move misses, the user of Hyper Beam will automatically use Hyper Beam during that turn. If at such a time Hyper Beam has 0 PP, Hyper Beam will still be used, and its PP will roll over 63.
And another interesting note, this time concerning only Wrap and Bind, is that while as normal moves they will deal no damage when used against a ghost-type, they will still immobilize it.
Type Effectiveness Differences
There are a few differences when it comes to a types' effectiveness against another type in RBY.
Ice is neutral to Fire instead of Not Very Effective.
Poison is Super Effective against Bug instead of Neutral.
Bug is Super Effective against Poison instead of Not Very Effective.
Ghost will NOT work on Psychic instead of being Super Effective regardless of what any RBY type chart tells you.
Stat Changing Moves
There are two types of stat changing moves. The normal ones that raise your stat by one or two levels, up to 6 such as Agility. The others are negative effects such as Paralysis or Burn. Now, if a pokemon gets its stat lowered by status, and then it increases that stat with a normal stat raising move its stat will be the same as if it had never been statused at all. Also, stat reductions due to stat ailments will be reapplied if an appropriate stat lowerer is used against the pokemon.
Practical applications of this:
You paralyze my Fire Spin Rapidash and, well, instead of making my Rapidash completely useless all I have to do is use Agility and I will again be fast enough to annoy the hell out of you with Fire Spin or maybe even Horn Drill.
Sleeping
When put to sleep you will never wake up and attack on the same turn such as in GSC. You will take a turn to wake up and you will then be allowed to attack again the turn after that. However, this doesn't mean you will sleep an extra turn in RBY when you use Rest. This can be pretty annoying because it freely allows a faster Pokémon to put you back to sleep without fear of being hit while the Pokémon wakes up.
1/256 Uncertainty
When deciding whether a move that targets the opponent hit, or whether or not a move critically hit, RBY mechanics formulates certainty as a value between 0 and 255, which is capped at 255 (for instance, when Persian uses Slash, even though Base Speed * 4 = 460 which is well over 255, it's brought back down to 255). The cart then randomly generates a number between 0 and 255 and, and if that number is less than 255, the move hits / CH's.
Due to this, there is always an extra 1/256 chance that any "100% accuracy" attack will miss, and that any high CH rate attack will miss (+~0.4%). The only exception is Swift, which does not perform this check, and thus cannot possibly miss.
Important Move Differences
Counter
This attack is able to counter damage taken as the result of a normal-type or fighting-type attack (it will fail against other physical type attacks), including reversed damage (from Counter/Bide), Seismic Toss damage, and recoil damage. On moves such as Fury Swipes, only the last hit can be Countered. Thus, a Fury Swipes user would not be in too much danger from Counter. The amount of damage countered is not influenced by type, and will hit ghost-types.
Counter in RBY can be used to counter back damage done on previous turns and not just on the same turn that it is used as long as my opponent's Pokémon doesn't use any move. (This includes turns during which an opponent is switched out, is frozen or defrosted, is fully paralyzed, or uses the non-damaging turn of a multi-hit move such as recharging, gathering sunlight, or glowing). For example: my Alakazam uses Seismic Toss on my opponent's Chansey as it switches in; I then switch to my Tauros, and if my opponent uses Counter, my Tauros will take 200 damage. This can be very annoying indeed.
Interestingly, Counter can criticaly hit, though it doesn't do a different amount of damage than it would have ordinarily. Also, this attack can work when the damage is done to the Substitute (even when the user has a substitute), to Counter back the amount of damage that would have been done to the user. This allows Counter to counter back damage that is up to double the user's HP; think Explosion and Selfdestruct. The exception to this is Countering a OHKO from behind a Substitute, which does
Dig and Fly
Well, first of all, Dig's Base Power is 100 in RBY instead of 60. While undergroud after using Dig you cannot be hit by Earthquake, and you cannot be hit by Thunder or Gust while you Fly.
Now the interesting part is if you get fully paralyzed or hit yourself in confusion while underground/in the air, not only will you stay there until you either switch out or use Dig/Fly again, but you will also keep the invulnerability until you switch out your Pokémon or use Dig/Fly again! You will be able to use any other attack your Pokémon may have and remain invulnerable to any attack (except Swift, Bide, and Transform) as if you were still underground/in the air.
Hyper Beam
You do not need to take a turn to recharge if you KO a Pokémon using Hyper Beam. If you do not KO, you will need a turn to recharge as usual. You also do not need to recharge if you break a substitute. You still will not have to recharge if Hyper Beam misses.
Reflect and Light Screen
Doubles user's defense rather than halving the opponent's attack (which can cause stat "roll-over", notably). Both moves are permanent until you switch out. They do not only last 2-5 turns and they are cancelled if you switch. A Critical Hit will also ignore them and Haze cancels them.
Rest
While using Rest removes Status effects like Paralysis and Burn, it does not allow you to regain the stat loss you suffered from any of them until you switch out.
Roar and Whirlwind
Both moves have no use whatsoever in link play. Unlike in the later versions they do not force switches. They just have no effect. Oh, and Whirlwind only has 85% accuracy.
Substitute
A Substitute will not block Status inducing moves, except Poison. It will not block Thunder Wave or Sleep Powder, for example, but will still block Toxic. It also blocks confusion moves such as Confuse Ray and stat reduction moves such as Screech. Substitute will, indeed, block attacks' secondary effects (ex: Body Slam can't paralyze if it hits a Substitute, even if it breaks) except for secondary confusion, for some reason. Substitute will not block the effect of partial trapping moves. A Substitute will also be the recipient of self-inflicted confusion damage.
Secondly, and this is where it gets interesting, if you use Selfdestruct, Hyper Beam, or Explosion on a Substitute, and the Substitute breaks, the consequence of your attack does not happen. For example: My Snorlax uses Selfdestruct on your Exeggutor's Substitute and your Substitute breaks; my Snorlax will miraculously survive the Selfdestruct no worse for wear than it was before. So, basically, don't use Substitute when you predict Explosion or Hyper Beam as it won�t help.
In addition if you use Substitute when your remaining HP is exactly 1/4 of your total it will cause your Pokémon to faint. Oh, and when an HP draining move breaks a Substitute, HP isn't drained.
Minor Move Differences
Bide
Unaffected by evade/accuracy modifiers. If the oppponent uses a non-damaging attack where it had used a damaging attack the previous turn, mid-Bide, then that non-damaging attack will count as having done the same damage as the previous turn's attack. (It is in this sense a more "flexible" counter, as it appends the last amount of damage done at the end of each turn, which is only reset when the opponent's attack misses).
Bite
Normal Type attack in RBY. Flinch Rate is 10% instead of 30%.
Blizzard
90% Accuracy instead of 70%, making it a formidable move.
Conversion
Changes the user's type to the opponent's type, rather than their own technique's type.
Disable
Rather than disabling the last move your opponent used, it will disable randomly one of his 4 moves. Also, lasts from 0 to 6 turn (same as ADV, but shifted to be one less than GSC) and causes Rage to build.
Dizzy Punch
Does not confuse.
Double-Edge
Base Power is 100 in RBY instead of 120 and the recoil is � of the damage dealt instead of 1/3.
Explosion
Base Power is 170 instead of 250, although it still halves your opponent's defense when it hits.
Fire Blast
Will burn 30% of the time instead of 10%.
Focus Energy
Not only will it not make your Critical Hit Ratio higher it will quarter it instead. Do not use under any circumstance.
Glare
Can paralyze ghosts while it cannot in the later versions.
Gust
Normal Type instead of Flying Type and also does not hit Pokémon using Fly.
Haze
Other than clearing all Pokémon stat changes / temporary states from the 2 Pokémon, including Reflect and Light Screen, it will also remove any status change from the opponent, such Paralysis, Sleep, Leech Seed, Confusion, etc. And, it will reset Toxic to ordinary poison on the user.
Hi Jump Kick and Jump Kick
If it misses, rather than having a recoil damage of 1/8 of what it would have dealt, it only makes you lose 1 HP.
Karate Chop
Normal Type instead of Fighting Type and also uses the High CH formula mentioned earlier.
Leech Seed
Absorbs 1/16 of your opponent's HP every turn (even when they have less than that amount remaining) instead of 1/8. Can be used in combination with Toxic, which is explained later.
Low Kick
Damage does not change depending on your opponent�s weight so that it's base power is always 50. It is also 90% accurate instead of 100%.
Metronome
The only technique which can't be called are itself and Struggle.
Mimic
Rather than mimicking the last move your opponent used it will mimic one of his 4 moves randomly. There is no restriction to this. It will learn any of your opponent's 4 moves including a move you already have as well. Additionally, when a Pokémon mimics a move, it gains 5 temporary PP of that move, which is separate from the PP of Mimic.
Night Shade and Seismic Toss
Will hit any Pokémon regardless of Type. Night Shade hits Normal types and Seismic Toss hits Gengar.
Poison Sting
Poisons 20% of the time instead of 30%.
Psychic
30% side effect Special Drop instead of 10%.
Rage
Quite possibly the stupidest move ever made. Damage from Rage will increase (1 level) as it does in Ruby/Sapphire as the raging Pokémon takes hits.
However, as soon as Rage hits, the raging Pokémon will stop obeying. It will not be able to use any other attack, it will not able to switch out, and it will also not lose any PP after the initial Rage hit. (Also, oddly, if it ever misses due to anything other than type immunity, its accuracy becomes 1/256.)
Razor Wind
75% accurate, instead of 100%.
Rock Slide
Does not flinch.
Selfdestruct
Base Power 130 instead of 200. Still halve your opponent�s defense when it hits.
Skull Bash
Does not raise your defense.
Sky Attack
Not a high CH move.
Stomp
Does not do double damage on Pokémon that have used Minimize.
Struggle
Normal Type, instead of typeless like in the later versions. Recoil is also 50%.
Swift
Swift is the only move that can hit Pokemons underground/in the air, after they used Dig or Fly.
Thunder
Paralyzes 10% of the time instead of 30%.
Toxic
Unlike in R/S (and like in GSC), Toxic will revert to regular poison status once you switch out. Can be used in combination with Leech Seed, which is explained later.
Tri Attack
Has no side effect. ie: It will not Paralyze, Burn, or Freeze.
Wing Attack
Base Power of 35 instead of 60.
Other Differences
Magnemite and Magneton
Absence of the Steel type in RBY makes Magnemite and Magneton pure Electric types.
Toxic + Leech Seed
Very roughly, using both in combination will make Leech Seed absorb more and more damage as Toxic's damage also increase.
For more detailed information:
Consider a variable N which removes N/16 of the Pok�mon's HP, referenced by both Toxic and Leech Seed. With Leech Seed, N normally isn't increased each turn, but with Toxic in effect as well, the counter is increased twice each turn, once after each of these recurrent effects. For instance, 1/16 from Toxic and 2/16 for Leech Seed, 3/16 from Toxic then 4/16 from Leech Seed, etc. By the fifth turn of that effect, it'll 1HKO the Pokémon. However, both are reset to 1/16 and don't increase again the first time you switch out, just like Toxic by itself.
Moves in which Multiple Instances of Damage Occur
Multi-hit and partial trapping moves always do the same amount of damage each hit; that is, whether or not it's a CH, and the damage dealt as a result of that calculation, is only done once, on the first turn.
Type Effectiveness Messages
A lot of times, the game will display the wrong type effectiveness messages. Most of the time it seems that if up against a dual-type the effectiveness message only consider's the pokemon's second type. (This isn't fully understood.)
Recovery Moves Failing
When a Pokémon�s HP are 255 or 511 below its max HP, recovery moves like Rest, Recover & Softboiled will fail� For instance, if Chansey is at 192 HP, which is 703 - 511, Softboiled fails.
0 Damage
For all it's worth: 0 damage will result in the attack missing.
Important RBY Differences
Pokémon versions Red/Blue/Yellow stand out for being some of the glitchiest video games ever made. However, in my opinion, it is what creates the RBY charm. Many things work differently in RBY than they do in the later generations where most of the glitches have been fixed.
This is a list of everything that works differently in RBY.
Important Differences
Special Stat
Instead of being divided in Special Attack & Special Defense like in GSC or RSFRLGE, there is only one Special Stat in RBY. It covers both Special Attack and Special Defense. Every move that raises or drops the Special Stat, such as Amnesia or Psychic, will therefore affect the Pokémon�s ability to both use special attacks and take special hits. In GSC, every Pokémon was given their Special split. They all, however, kept their original Special Stat value for either Special Attack or Special Defense. While they managed to tone down several Pokémon that were overpowered (ex: Alakazam) and make some others better (ex: Hitmonlee), they also weakened some that werent especially strong (ex: Tangela) and made some that were already strong ever better (ex: Snorlax).
Critical Hits
In RBY the Critical Hit Ratio is based on Base Speed rather than having a set Ratio. Which means that, yes, faster Pokémon will Critical Hit more than slower ones. This is very important to consider in RBY as most of the faster Pokémon will have a Critical Hit ratio higher than 20%. The Ratio, being based on BASE speed, will not change if the Pokémon is paralyzed or suffers a speed drop.
Formula to calculate a Pokémon's CH ratio : CH%=BaseSpeed*100/512.
In addition, when moves Critical Hit, they will ignore any stat change you and your opponent might have, beneficial or otherwise. For example, if you used Amnesia 3 times to maximize your Special stat and then score a Critical Hit, you will actually do less damage than you would have if you didn�t, only doing twice as much as you would normally do without boosts. Critical Hits will also ignore Reflect and Light Screen.
High Critical Hit Moves
Razor Leaf, Slash, Crabhammer, and Karate Chop. Like normal Critical Hits they are also based on Base Speed and the formula used for those mean they nearly always give a Critical Hit.
The CH ratio formula for High Critical Moves in RBY is : CH%=BaseSpeed*100/64.
Freezes
There is only two ways to unfreeze, and those are either by getting hit by a Fire type attack or if your opponent uses Haze while your frozen Pokémon is in play. The frozen Pokémon will never thaw by itself.
One-Hit KO Attacks
Based on Speed, but not on Base Speed. The attack will always fail if you are slower than your opponent. It may only succeed if you are faster or have the same speed.
Trapping Moves
Wrap, Fire Spin, Clamp, and Bind. Instead of preventing switching they prevent your opponent from attacking after it hits during the whole 2-5 turns the attack may last. So, if you are faster than your opponent, you can keep using Wrap over and over again and they cannot hit you back. Only the first hit of the 2-5 attack sequence wastes a PP and is subject to miss due to accuracy. The wrapping Pokémon isn't allowed to use any other attack until the 2-5 turn sequence ends. In addition, a Critical Hit is only also calculated for the first hit, if it does score a Critical Hit, every remaining sequence hit will do that amount of damage. Using a wrapping move can also be used to get a free switch. For example: Cloyster uses Clamp on an incoming Starmie. Cloyster can switch out freely the turn after while Starmie will stay immobilized for that turn, but will still be released from the Clamp. The pokemon will also remain immobilized if the user of the partial trapping technique is fully paralysed mid sequence but the sequence will end.
If a wrapped Pokémon switches out while in the middle of a wrap sequence, the sequence resets and the accuracy must be tested again on the switch and another PP is wasted. If at such a time the trapping move has 0 PP, it will still be used against the incoming pok�mon. After that use, the current PP of the trapping move will roll over to 63.
If the target of the partial trapping move just used Hyper Beam, it won't have to recharge if the partial trapping move misses on the recharge turn. Additionally, if the user of the partial trapping move attacks before the user of Hyper Beam during a recharge turn and the partial trapping move misses, the user of Hyper Beam will automatically use Hyper Beam during that turn. If at such a time Hyper Beam has 0 PP, Hyper Beam will still be used, and its PP will roll over 63.
And another interesting note, this time concerning only Wrap and Bind, is that while as normal moves they will deal no damage when used against a ghost-type, they will still immobilize it.
Type Effectiveness Differences
There are a few differences when it comes to a types' effectiveness against another type in RBY.
Ice is neutral to Fire instead of Not Very Effective.
Poison is Super Effective against Bug instead of Neutral.
Bug is Super Effective against Poison instead of Not Very Effective.
Ghost will NOT work on Psychic instead of being Super Effective regardless of what any RBY type chart tells you.
Stat Changing Moves
There are two types of stat changing moves. The normal ones that raise your stat by one or two levels, up to 6 such as Agility. The others are negative effects such as Paralysis or Burn. Now, if a pokemon gets its stat lowered by status, and then it increases that stat with a normal stat raising move its stat will be the same as if it had never been statused at all. Also, stat reductions due to stat ailments will be reapplied if an appropriate stat lowerer is used against the pokemon.
Practical applications of this:
You paralyze my Fire Spin Rapidash and, well, instead of making my Rapidash completely useless all I have to do is use Agility and I will again be fast enough to annoy the hell out of you with Fire Spin or maybe even Horn Drill.
Sleeping
When put to sleep you will never wake up and attack on the same turn such as in GSC. You will take a turn to wake up and you will then be allowed to attack again the turn after that. However, this doesn't mean you will sleep an extra turn in RBY when you use Rest. This can be pretty annoying because it freely allows a faster Pokémon to put you back to sleep without fear of being hit while the Pokémon wakes up.
1/256 Uncertainty
When deciding whether a move that targets the opponent hit, or whether or not a move critically hit, RBY mechanics formulates certainty as a value between 0 and 255, which is capped at 255 (for instance, when Persian uses Slash, even though Base Speed * 4 = 460 which is well over 255, it's brought back down to 255). The cart then randomly generates a number between 0 and 255 and, and if that number is less than 255, the move hits / CH's.
Due to this, there is always an extra 1/256 chance that any "100% accuracy" attack will miss, and that any high CH rate attack will miss (+~0.4%). The only exception is Swift, which does not perform this check, and thus cannot possibly miss.
Important Move Differences
Counter
This attack is able to counter damage taken as the result of a normal-type or fighting-type attack (it will fail against other physical type attacks), including reversed damage (from Counter/Bide), Seismic Toss damage, and recoil damage. On moves such as Fury Swipes, only the last hit can be Countered. Thus, a Fury Swipes user would not be in too much danger from Counter. The amount of damage countered is not influenced by type, and will hit ghost-types.
Counter in RBY can be used to counter back damage done on previous turns and not just on the same turn that it is used as long as my opponent's Pokémon doesn't use any move. (This includes turns during which an opponent is switched out, is frozen or defrosted, is fully paralyzed, or uses the non-damaging turn of a multi-hit move such as recharging, gathering sunlight, or glowing). For example: my Alakazam uses Seismic Toss on my opponent's Chansey as it switches in; I then switch to my Tauros, and if my opponent uses Counter, my Tauros will take 200 damage. This can be very annoying indeed.
Interestingly, Counter can criticaly hit, though it doesn't do a different amount of damage than it would have ordinarily. Also, this attack can work when the damage is done to the Substitute (even when the user has a substitute), to Counter back the amount of damage that would have been done to the user. This allows Counter to counter back damage that is up to double the user's HP; think Explosion and Selfdestruct. The exception to this is Countering a OHKO from behind a Substitute, which does
Dig and Fly
Well, first of all, Dig's Base Power is 100 in RBY instead of 60. While undergroud after using Dig you cannot be hit by Earthquake, and you cannot be hit by Thunder or Gust while you Fly.
Now the interesting part is if you get fully paralyzed or hit yourself in confusion while underground/in the air, not only will you stay there until you either switch out or use Dig/Fly again, but you will also keep the invulnerability until you switch out your Pokémon or use Dig/Fly again! You will be able to use any other attack your Pokémon may have and remain invulnerable to any attack (except Swift, Bide, and Transform) as if you were still underground/in the air.
Hyper Beam
You do not need to take a turn to recharge if you KO a Pokémon using Hyper Beam. If you do not KO, you will need a turn to recharge as usual. You also do not need to recharge if you break a substitute. You still will not have to recharge if Hyper Beam misses.
Reflect and Light Screen
Doubles user's defense rather than halving the opponent's attack (which can cause stat "roll-over", notably). Both moves are permanent until you switch out. They do not only last 2-5 turns and they are cancelled if you switch. A Critical Hit will also ignore them and Haze cancels them.
Rest
While using Rest removes Status effects like Paralysis and Burn, it does not allow you to regain the stat loss you suffered from any of them until you switch out.
Roar and Whirlwind
Both moves have no use whatsoever in link play. Unlike in the later versions they do not force switches. They just have no effect. Oh, and Whirlwind only has 85% accuracy.
Substitute
A Substitute will not block Status inducing moves, except Poison. It will not block Thunder Wave or Sleep Powder, for example, but will still block Toxic. It also blocks confusion moves such as Confuse Ray and stat reduction moves such as Screech. Substitute will, indeed, block attacks' secondary effects (ex: Body Slam can't paralyze if it hits a Substitute, even if it breaks) except for secondary confusion, for some reason. Substitute will not block the effect of partial trapping moves. A Substitute will also be the recipient of self-inflicted confusion damage.
Secondly, and this is where it gets interesting, if you use Selfdestruct, Hyper Beam, or Explosion on a Substitute, and the Substitute breaks, the consequence of your attack does not happen. For example: My Snorlax uses Selfdestruct on your Exeggutor's Substitute and your Substitute breaks; my Snorlax will miraculously survive the Selfdestruct no worse for wear than it was before. So, basically, don't use Substitute when you predict Explosion or Hyper Beam as it won�t help.
In addition if you use Substitute when your remaining HP is exactly 1/4 of your total it will cause your Pokémon to faint. Oh, and when an HP draining move breaks a Substitute, HP isn't drained.
Minor Move Differences
Bide
Unaffected by evade/accuracy modifiers. If the oppponent uses a non-damaging attack where it had used a damaging attack the previous turn, mid-Bide, then that non-damaging attack will count as having done the same damage as the previous turn's attack. (It is in this sense a more "flexible" counter, as it appends the last amount of damage done at the end of each turn, which is only reset when the opponent's attack misses).
Bite
Normal Type attack in RBY. Flinch Rate is 10% instead of 30%.
Blizzard
90% Accuracy instead of 70%, making it a formidable move.
Conversion
Changes the user's type to the opponent's type, rather than their own technique's type.
Disable
Rather than disabling the last move your opponent used, it will disable randomly one of his 4 moves. Also, lasts from 0 to 6 turn (same as ADV, but shifted to be one less than GSC) and causes Rage to build.
Dizzy Punch
Does not confuse.
Double-Edge
Base Power is 100 in RBY instead of 120 and the recoil is � of the damage dealt instead of 1/3.
Explosion
Base Power is 170 instead of 250, although it still halves your opponent's defense when it hits.
Fire Blast
Will burn 30% of the time instead of 10%.
Focus Energy
Not only will it not make your Critical Hit Ratio higher it will quarter it instead. Do not use under any circumstance.
Glare
Can paralyze ghosts while it cannot in the later versions.
Gust
Normal Type instead of Flying Type and also does not hit Pokémon using Fly.
Haze
Other than clearing all Pokémon stat changes / temporary states from the 2 Pokémon, including Reflect and Light Screen, it will also remove any status change from the opponent, such Paralysis, Sleep, Leech Seed, Confusion, etc. And, it will reset Toxic to ordinary poison on the user.
Hi Jump Kick and Jump Kick
If it misses, rather than having a recoil damage of 1/8 of what it would have dealt, it only makes you lose 1 HP.
Karate Chop
Normal Type instead of Fighting Type and also uses the High CH formula mentioned earlier.
Leech Seed
Absorbs 1/16 of your opponent's HP every turn (even when they have less than that amount remaining) instead of 1/8. Can be used in combination with Toxic, which is explained later.
Low Kick
Damage does not change depending on your opponent�s weight so that it's base power is always 50. It is also 90% accurate instead of 100%.
Metronome
The only technique which can't be called are itself and Struggle.
Mimic
Rather than mimicking the last move your opponent used it will mimic one of his 4 moves randomly. There is no restriction to this. It will learn any of your opponent's 4 moves including a move you already have as well. Additionally, when a Pokémon mimics a move, it gains 5 temporary PP of that move, which is separate from the PP of Mimic.
Night Shade and Seismic Toss
Will hit any Pokémon regardless of Type. Night Shade hits Normal types and Seismic Toss hits Gengar.
Poison Sting
Poisons 20% of the time instead of 30%.
Psychic
30% side effect Special Drop instead of 10%.
Rage
Quite possibly the stupidest move ever made. Damage from Rage will increase (1 level) as it does in Ruby/Sapphire as the raging Pokémon takes hits.
However, as soon as Rage hits, the raging Pokémon will stop obeying. It will not be able to use any other attack, it will not able to switch out, and it will also not lose any PP after the initial Rage hit. (Also, oddly, if it ever misses due to anything other than type immunity, its accuracy becomes 1/256.)
Razor Wind
75% accurate, instead of 100%.
Rock Slide
Does not flinch.
Selfdestruct
Base Power 130 instead of 200. Still halve your opponent�s defense when it hits.
Skull Bash
Does not raise your defense.
Sky Attack
Not a high CH move.
Stomp
Does not do double damage on Pokémon that have used Minimize.
Struggle
Normal Type, instead of typeless like in the later versions. Recoil is also 50%.
Swift
Swift is the only move that can hit Pokemons underground/in the air, after they used Dig or Fly.
Thunder
Paralyzes 10% of the time instead of 30%.
Toxic
Unlike in R/S (and like in GSC), Toxic will revert to regular poison status once you switch out. Can be used in combination with Leech Seed, which is explained later.
Tri Attack
Has no side effect. ie: It will not Paralyze, Burn, or Freeze.
Wing Attack
Base Power of 35 instead of 60.
Other Differences
Magnemite and Magneton
Absence of the Steel type in RBY makes Magnemite and Magneton pure Electric types.
Toxic + Leech Seed
Very roughly, using both in combination will make Leech Seed absorb more and more damage as Toxic's damage also increase.
For more detailed information:
Consider a variable N which removes N/16 of the Pok�mon's HP, referenced by both Toxic and Leech Seed. With Leech Seed, N normally isn't increased each turn, but with Toxic in effect as well, the counter is increased twice each turn, once after each of these recurrent effects. For instance, 1/16 from Toxic and 2/16 for Leech Seed, 3/16 from Toxic then 4/16 from Leech Seed, etc. By the fifth turn of that effect, it'll 1HKO the Pokémon. However, both are reset to 1/16 and don't increase again the first time you switch out, just like Toxic by itself.
Moves in which Multiple Instances of Damage Occur
Multi-hit and partial trapping moves always do the same amount of damage each hit; that is, whether or not it's a CH, and the damage dealt as a result of that calculation, is only done once, on the first turn.
Type Effectiveness Messages
A lot of times, the game will display the wrong type effectiveness messages. Most of the time it seems that if up against a dual-type the effectiveness message only consider's the pokemon's second type. (This isn't fully understood.)
Recovery Moves Failing
When a Pokémon�s HP are 255 or 511 below its max HP, recovery moves like Rest, Recover & Softboiled will fail� For instance, if Chansey is at 192 HP, which is 703 - 511, Softboiled fails.
0 Damage
For all it's worth: 0 damage will result in the attack missing.