Masterpiece.
I really like the thought that was put into the possible relationship dynamics and their futures. It's a grim prospect to ponder for any pairing, but it's an amazing depiction of how Reimu's immediate desires could snowball into long-lasting consequences, in a narrative sense. It isn't exactly anyone's fault that tragedy ensues, it's simply how their dynamics would play out if nothing were to be done about it, and I appreciate that.
I also enjoyed Reimu's character growth, and the emphasis on understanding the rationale behind why she wants to uphold her lifestyle as it is, instead of just staying rude to run away from her problems. The final sequence was very satisfying.