Battle Moon Wars/Secrets

Good Ending: Finish the game on Hard difficulty. You need to obtain 41 or more Battle Masteries.

New Game Plus: Complete the game. You carry over 50% of your BP/FP, and all of your items.
You will also have the option to let enemies start the game with anywhere between 1 to 10 upgrades.

Character and Sound Dictionary: Complete the game.

First Bonus Chapter, 52: 45 Battle Masteries must be obtained.

Bonus Chapters 53-1 through 53-4: All 50 Battle Masteries must be obtained.

Magical Girl Amber and Saber Lily: Finish Bonus Chapters 53-1 through 53-4.
When starting a New Game Plus, Amber and Lily will be available to deploy.

Satsuki Yumizuka: Defeat Satsuki with Shiki at least twice in Episodes 5, 20, and 21; she will join after Episode 29. Super Route Only (Unconfirmed).
If a save with Satsuki unlocked is imported into New Game Plus, Satsuki will be unlocked automatically regardless of route.

Mecha Hisui: If Kohaku and Hisui's combined kill count is 45 or more, Mech Hisui will join after Episode 47. Real Route Only (Unconfirmed).
Like Satuski, if a save is imported to New Game Plus with Mecha Hisui unlocked, they will be unlocked automatically regardless of route.

Abnormal Agonist (Equippable Item): Reward for importing a clear save into New Game Plus.