The Hero's Path

1. For some reason, the quest with Captain Bronver didn't work. After he escapes the island, you approach him, and there's no reaction.

Damn, I don't even know. The code between versions 1.2 and 1.3 didn't change there, and it doesn't seem like anything is broken in it. I'll keep it in mind for the future; maybe someone else will encounter it too.

2. There are some issues with the new potion - Alchemy. (See the pictures)

This happens to me sometimes too - inscriptions that aren't loaded directly from the file, but are dynamically composed using the tag value=xxx, sometimes don't display. If you flip the page back and forth, everything usually becomes normal. I suspect this is some kind of bug in the game's code, so I couldn't do anything about it. If this only occurred with Alchemy and constantly, I have no ideas.

I drink a bottle of chemicals
Alchemy 9 appears out of nowhere.

Alchemy was added because it was probably already part of the potion initially (the screenshot shows that in the potion's properties, there's a comma at the end, meaning the last property simply wasn't displayed). Did this happen only once, or constantly? Are there any old and new versions of the map in the game folder at the same time?

3. Battle with the Demon Lord. This is all I could gather in a year (without losses), and about 20 bottles of very strong chemicals were used...

The trick with chemicals is that it's not effective to drink a bunch of potions in a row, as each subsequent one will be weaker. At the same time, the Alchemy skill level allows you to mix a larger number of ingredients, which means there is an opportunity to create composite potions (more effective compared to single ones), which I usually did. Plus, instead of a bunch of average potions, it's better to make one, but with maximum effectiveness. For example, one potion - attack + defense, the second - initiative + health, the third - morale + luck. In total, 3 potions with 100%/80%/60% effectiveness are made and drunk, which cover almost all the necessary parameters. Last time, I accumulated so many elements that I mixed one potion similar to +300 attack and +300 defense, and I didn't need anything else.