The top-layer of endings are the 'good' endings, the middle-layer are the 'neutral' endings, and the bottom-layer are the 'bad' endings.
Ending Hints below:
Most of the endings are received after attempting to charm the White King based on if you complete or fail your three main objectives (getting the White Queen killed, promoting to a Queen piece, and charming the King himself).
It's possible to fail the skill check for charming the White King (Charm the King) or killing the Black King (Slay the King) without getting a game over, which is how you'd unlock those extra endings.
Failing the White Queen's skill check (Trick her into a trap) will set you on a unique route :]
Maybe I should add an indicator that these checks can be failed in an update for more clarity...