Oh, and I tried to do all the puzzles (100%) and not do all of them.
The ending is the same, Youmu saying that Reisen took too long.
It would be better to have two endings, both with Youmu and Reisen ending together.
But the lack of rection from Youmu when Reisen go right after her without completing anymore puzzles, that is disappointing.
And it would be nice to have a continuation. With Youmu helping Reisen in some puzzles, but outside Eientei.
The story/ending were definitely limited by the jam deadline, but I think the most I would've done for that case is change a line or two of dialog rather than writing a separate ending, 'cus it's not the main point of their conflict.
As far as a continuation goes, I am planning to make a new game/expansion with the same puzzle mechanics, but it'd be with original characters instead of Touhou