Big Touhou fan, so everything is heavily bias
For a doujin, it is exceptionally done.
The land of (Gensoukyou) & its inhibitants done so beautifully, so colourful & magical. Its mysterious and filled with spritis, youkais, gods & other beings. Each with distinctly varied, unique & quirkly personality & design-wise (though they always ends up drunk). Its exactly how a Touhou fan would imagine. Definitely a treat to see your favourite Touhou chars and incidents come to live in animation
Also music is crazy awesome, everytime I hear it, my soul quivers with excitement, intense energy and profound emotions, it just resonates so well
For non-fans, suggest to research/know the names and relation of the main characters. This anime makes minimal effort with background, thus the plot may seem disjointed
Tbh, am not a Touhou gamer, but I visit every Komiket for the doujin music & artworks. And sure enough I enjoyed the animation & Senya's beautiful voice in the OSTs. 10/10 for me!