Final Fantasy VI Reimagined

First of all, thank you DrakeyC for a fantastic mod. I am really enjoying it.

I ran into the same bug that LoungingLock reported.
I was also able to get past it by copying one of my save states to an unpatched rom, playing past the crash, then making another save state and copying it back to my patched rom.

It happens right after this scene.
   

Instead of transitioning to the battle where the other 3 characters fight Kefka, instead they go here
   

Are you playing the latest patched version? Also, don't use unpatched roms to play around bugs like this, as other users have said when they tried it, you'll just run into other problems.

Yes, I believe I have the latest version. I downloaded it from here on Nov 7 and the change log says Oct 30 was the latest update.

Redownload now just to be sure, and play from before the Sealed Gate scene.

I think I found a bug/crash. If gogo mimics gau when he does if claw attack from the ultimate weapon the game freezes

Roger, I'll have a look. Thanks for reporting that.

Excuse me, but how do I fix that bug during the Cave to the Sealed Gate sequence, I already have the latest patch installed rn so what should I do next?

If you have Discord, can you join the FF6hacking server and ping me to share a save file to look at?

Version 1.5 is officially out! This update features more QoL updates, graphical enhancements, gameplay tweaks, and more.

- Shadow is now able to accompany the party to Vector. If he's already in the party when you complete Zozo, you'll have the option to keep him on, or you can go hire him after Zozo. If hired at this point, he will leave when the party returns to Zozo after the Magitek Research Facility.
- Espers can now be swapped directly between party members. When attempting to equip an Esper already in use, a message appears displaying who has it and the option to remove it from them.
- Gau's Rage list now displays enemies alphabetically, and in the field menu each enemy has a description listing their Rage attacks, elemental weakness, and if they are undead
- Mog's Dance list now displays the attacks he can use under their effects
- Common and Rare items can now both be stolen from enemies; if you get one, you can keep stealing to try and get the other.
- Terra, Celes, Sabin, and Cyan, learn their natural skills at slightly lower levels (Magic, Blitz, and Bushido, respectively)
- The Jidoor relic shop in the WoR now sells the Sneak Ring; previously it was unavailable in the WoR.
- Albrook in the WoB no longer sells elemental scrolls; as Shadow can now be brought to the southern continent, they were deemed too powerful to be buyable at this point in the game.
- The crane in Zozo that lets the party descend to the ground has been moved further up the tower, to be more useful as a shortcut.
- The left-hand room in the Coliseum contains a new feature, where you can enter some small rooms to encounter some  enemies from the World of Ruin, averting them being missable on the Veldt. Not ALL enemies are here, just ones that are easily overlooked because they only appear in one spot and/or in an unrevisitable location. 
- Soft reset function added: at any time in the field, holding L+R+START+SELECT at once will reset the game.
- The Angel Brush now heals HP when attacking. The Magus Rod drains MP.
- Zantetsuken's slicing effect has been fixed.
- A crash when recruiting Gogo with Setzer in the party has been fixed.
- Kefka's final boss AI script tweaked.
- Celes has a new field sprite.
- Wrexsoul has a new, unique field sprite.
- Minor aesthetic changes to the Magitek Research Facility; caution stripes for various points that are traversible. A pipe in the MRF that previously sent the party back to the entrance of the second room now connects to the balcony overlooking the garbage chute instead, allowing for easier routing to get treasures.
- Some new world map tiles, particularly for Doma Castle, Zozo, and the Coliseum.
- The party now receives a particular key item as a token of their victory upon defeating Gilgamesh.
- The Dirt Dragon's lair in the Dragon Shrine now has treasures to find in it.
- The Ice Dragon's lair in the Dragon Shrine now requires you to talk to the Ice Dragon to battle it; previously the fight triggered automatically when approaching it.
- The Red Dragon's lair now has visual indicators of where the layout of the area has changed when hitting switches; the party will automatically face in the direction of whatever changed.

There's a chest above the room containing Ronin/Oborozuki in the Ancient Castle, and it had been opened on its own/empty in my playthrough. I ignored it and continued the game normally, but now I'm aware that's supposed to contain the sword Zantetsuken. The thing is I don't know why the chest is empty in my playthrough because from reading the this thread, the bug was reported and fixed in October last year, and I first downloaded the patch this February before updating to 1.5 a couple of days ago(I still haven't finished the game yet). To note, I originally went through the castle in the previous version before 1.5, and recently checked again from an older save file in the current version and find it still empty. And if it helps, I did Cyan's dreams before this and the only things left to do are the Fanatics Tower, Roccabara Island, and Gilgamesh before Kefka.

This is my first time properly playing through FFVI from beginning to end, and I thought the opened chest is for a story reason so I didn't think much of it until now. While I personally might not use the sword and doesn't want go down to the castle again, I thought I should mention this just in case.