This page contains unmarked SPOILERS. Beware!
Post-game is a term used to refer to content that occurs late in the game, typically after completing part 4 of Take Me On, defeating all 9 main game Archangels, or defeating Aleph Null.
After Part 4 of Take Me On
After Defeating Main Game Archangels & Aleph Null
After Part 4 of Take Me On & Defeating Aleph Null