My pleasure. I speedrun myself and care a lot about the speedrunning community. Im available on Discord if you think of anything. I've decided to continue working on this project and create a second part to the story and will want to add speedrun optimisations into that section of the game too.
I double checked the final Boss code and the chain shot regeneration code is working fine. But yeah, it's just very precise to time the next chain shot to hit right after he loses his i-frames while he is moving so fast.