Here is the full list of all 17 Corpse Party achievements.
Completed Tooth.
Attained all endings and found every name tag.
Viewed every ending.
Completed She Knows a Key.
Completed Meeting of the Minds.
Completed A Gentleman's Errand.
Attained the alternate ending to Chapter 5.
Attained all endings in Chapter 4.
Attained all endings in Chapter 3.
Attained all endings in Chapter 2.
Attained all endings in Chapter 1.
Attained the true ending to Chapter 5.
Attained the "loop ending" to Chapter 5.
Completed Chapter 4.
Completed Chapter 3.
Completed Chapter 2.
Completed Chapter 1.