Well... It was... intense! The conflict between Cassidy's affection for her sister and her religious trauma is really well crafted in the game! I appreciated the fatalism a lot: the fact that, no matter what, Cassidy cannot overcome what she really believes or feels and is doomed to the ending she gets echoes a lot to a lot of things I enjoy in stories (the tragic concept of fatum really speaks to me!).
The background was amazingly chosen, it really looked like the end of the world somehow, haha! Also, the sprite was amazing!! A great mix between the horrifying appearance of angels (although they are rarely portrayed as such nowadays) and a more human figure which would confront Cassidy to the sister I suppose she lost in the foundation? I really need to play Pride to have a better glimpse at the whole picture though!
Oh, and speaking of titles: what's the meaning of Shibboleth, if I may ask?
Overall, a great entry with heavy themes, and perfect use of the restrictions of the jam, especially considering you made this game in just one day, wow! (+) the logo looks VERY GOOD????????? Damn, your calligraphy skills really show!!