It reminds me of the bit in The Ring (US) in the video, but only it's a mirror of the same shape on similar wallpaper, with the girl sliding backwards away from it as she's reflected in it.
Anyway, I really like how Murasa and Nue look in this picture. On a slightly off-topic note, are there any doujin games where you play as either of those two? I always find the boss character far more interesting than the playable characters on the odd occasion I've played Touhou and when I see Touhou fan art.