Here is the full list of all 19 Corpse Party: Sweet Sachikos Hysteric Birthday Bash achievements.
Completed the Extra Chapter.
Attained all endings in the Extra Chapter.
Unlocked all other achievements.
Completed Chapter 8.
Completed Chapter 7.
Attained all endings in Chapter 7.
Attained all endings in Chapter 6.
Completed Chapter 6.
Completed Chapter 5.
Attained all endings in Chapter 5.
Completed Chapter 4.
Attained all endings in Chapter 4.
Attained all endings in Chapter 3.
Completed Chapter 3.
Completed Chapter 2.
Attained all endings in Chapter 2.
Completed Chapter 1.
Attained all endings in Chapter 1.
Completed Chapter 0.