This patch is now out of date, see this post for the newest one.
I have uploaded a new patch that fixes several bugs, rebalances some Master Trainers, places a Sun Stone before postgame, and adds more functionality to the Battle Anim Speed option. The link in the first post has been updated, but you can also grab it from here:
https://github.com/Deokishisu/FRLG-Plus/releases/tag/v1.3.0
• Mewtwo will now not respawn incorrectly after its battle in the two new Cerulean Cave layouts.
• Bill on Cinnabar Island should now no longer walk through buildings when the player declines to go with him to One Island.
• Fixed a tile error on Four Island's Base.
• Master Raichu's Attack and Defense stats were reduced by 10% and its Speed stat was increased by 10%.
• Master Mr. Mime is now Adamant instead of Modest.
• Several Master Trainer Pokemon had incorrect IVs which were fixed.
• Fixed incorrect line breaks in the Battle House woman's text.
• Fixed vanilla bug where the AI would decide to use Foresight based on the user's type and stats instead of the target's.
• Fixed vanilla bug where the AI would incorrectly decide to try to stall with semi-invulnerable moves while a weather effect is damaging them.
• Fixed vanilla bug where the AI would decide to use Facade based on the target's status instead of the user's.
• Fixed Assist, Block, Camouflage, Charge, Conversion 2, Follow Me, Grudge, Helping Hand, Imprison, Ingrain, Magic Coat, Mean Look, Memento, Mimic, Mud Sport, Nightmare, Pain Split, Recycle, Refresh, Role Play, Skill Swap, Slack Off, Snatch, Softboiled, Spider Web, Tail Glow, Water Sport, Wish and Yawn displaying an incorrect accuracy value from vanilla. Vital Throw was fixed before the initial release.
• A Sun Stone has been added to Kanto that is available before the postgame, making Bellossom obtainable much earlier.
• When Battle Anim Speed is set to fast or instant, battle transitions are now skipped and instantly cut to the battle. Battle transitions will only play for trainers with the mugshot transition effect.
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I haven't had a lot of time to work on this of late, so I wanted to put out a bug fix release so that some of the more egregious bugs and oversights weren't sitting here for months as well as add quick functionality to skip battle transitions. Thus, bag sorting, binding more than one item to select, and Colosseum Bonus Disc compatibility were not included in this release.
All in all, the Battle Anim Speed setting now shaves off about six seconds from the beginning of
every battle, which makes things feel so snappy at the expense of it not being as pretty.
Here's an example of how quick it is for wild battles: