The intended ruleset is automatically loaded in the randomizer when you open the ROM, but can be played vanilla as well.
Balance:
Forced starter choice setting. (only in the randomizer)
Up to 20 renewable heals in total. (Pokemon Centers, Mom, S.S. Anne, Silph Co., Pokemon Tower)
* Remaining heals are in your trainer card.
* Free heals aren't counted towards this.
1 catch/faint per route/dungeon.
* Subsequent faints grant no exp or EVs.
* Subsequent catches immediately break out.
Locked into gyms until you earn the badge.
HMs become single-use.
Trainers only reward 5 Pokedollars.
Bosses have significantly raised prize money.
Reduce sell prices by 5x.
Raise Revive and Max Revive price to 16000.
Remove Celadon Department X Items store.
Remove Game Corner machines using/giving coins.
Remove Move Deleter.
Remove Vs. Seeker.
Combat:
Fainted Pokemon can't be healed until they are revived.
Fainted Pokemon can't be deposited in the PC.
Withdrawing a Pokemon out of the PC sets their HP to 1.
Spore has Sleep Powder's accuracy when the player uses it.
Struggle recoil now deals 25% of your max HP.
Pokemon with Pure Power / Huge Power become Plus / Minus for players.
670+ BST Pokemon are granted Truant for players.
Forced "Set" to always be enabled.
Remove combat effects from the following items:
* Poke Flute
* Blue Flute
* Yellow Flute
* Red Flute
* Amulet Coin
* Lucky Egg
* Leftovers
Misc:
Rock Tunnel no longer requires Flash.
Renewable hidden items generate on new game rather than every 1500 steps.
Flatten wild encounter chances, no more rare Pokemon slots.
Remove Sevii Islands.
BST, IV, and Nature display.
* Red is positive, purple is negative.
* + = 21+ IV
* - = 10- IV
Show Hidden Power typing in the summary and battles.
Add BW2+ Repel re-use prompt.
Guarantee runs after 3 tries.
Remove help system.
Remove PokeCenter lag.
Remove a lot of intro dialogue and tutorials.
* Oak's intro has been cut down.
* No more parcel.
* Old man is dead.
Free running shoes, and running indoors.