To point out one specific thing I liked about this one--being as vague as possible so as not to spoil things--the idea that a character's previous adventures actually had a lasting impact on them is interesting in this context. Often even official/canon Touhou stuff more or less starts and ends with a kind of sitcom status quo for the characters (i.e., Marisa and Reimu should be about 38 years old but exist in eternal comedy manga time). I'm fine with that, I like comedy manga etc., but I like seeing the alternative too.