- After each stage, you're given the option to quit out instead of continuing. This seems like a pointless feature at first. However, this is a game where you can lose Spirits at the end of a stage, be it from timing out a boss or doing poorly in the Shrine of Farewell. Although you can evade the time-out penalty by simply exiting the game before time runs out (your score will still save), once you enter the Shrine you will lose all of your spirits until the end of the stage, so if your next stage is the Shrine, the "exit instead of contining to the next stage" can be a blessing.
- The Apostles of the Seed's BGM is an arrangement of Radio Zonde's stage 1-3 boss theme, Past Rising Again. Radio Zonde is often seen as a Spiritual Predecessor to this game; it also uses terms like "Sol", "Luna", and "Stella". There are two protagonists, and moreover the Apostles share similar attacks with them. Those two protagonists, could they be...?
- If the Bad Ending after timing out Rex Cavalier and the Japanese wiki which notes that "Prayer" could also have meant "Player" are anything to go by, it could very well mean that many other people similar to the Graveyard may have attempted to enter the Cardinal Shaft in the past, but have fallen victim to its Karma Compressor System and become Prayers...including the characters from Radio Zonde. Which, if you think about it hard enough, also puts a different spin on the phrase "Keep Your Dignity".