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 "loop ending" to Chapter 5.
Attained the alternate ending to Chapter 5.
Attained the true ending to Chapter 5.
Attained all endings in Chapter 4.
Completed Chapter 4.
Attained all endings in Chapter 3.
Completed Chapter 3.
Attained all endings in Chapter 2.
Completed Chapter 2.
Attained all endings in Chapter 1.
Completed Chapter 1.