Sorry for the delay, the last few days were… a bit long.
Unfortunately, I couldn’t make much progress on the Flowey fight, I needed ideas for his attacks. But, now I have them, so yesterday I started working on them.
This fight will be shorter than Chara’s, but it will try to introduce Floweys new character. Flowey is still a mean plant, but after the genocide run, he realises, that he can die. He was lucky with Frisk’s reset, but he will do anything to stay alive. (Well, as long as he gains back the ability to save.) Even if this means cooperating with Frisk. But for that Frisk needs to talk with him about the real enemy.
This will be, where the story start branching out, so from now on your choices will do something. Not just if you kill or spare (and if you stay on the genocide path, you really not going to like what happens next), but what do you tell to the others.

For example: If you tell Toriel, that Chara is alive.

And of course, Frisk’s personality. I have the ideas, but I need to create a good character evolution for her. And I think, this will be the hardest part.