Here is the full list of all 60 1bitHeart achievements.
Get GAME OVER
Play the Extra Story
Befriend Mikado
Befriend Tobari
Complete all friendships
Befriend Kirai
Befriend Kotora
Befriend Nomiya
Befriend Misane
Give someone chocolate for the first time
See the Happy End
Befriend Momori
Befriend Misato
Befriend Akashi
Befriend Moroku
Befriend Sora
Befriend Chino
Befriend Rocca
Befriend Kirara
Befriend Ryuuri
Befriend Yuuto
Befriend Hiyu
Befriend Jin
Befriend Azusa
Befriend Asuto
Befriend Enri
Befriend Hitohito
Befriend Mary
Befriend Meru
Befriend Saaya
Make 25 friends
Befriend Izuchi
Befriend Meu
Befriend Sagara
See the Normal End
Befriend Potete
Befriend Aira
Befriend Akitaka
Befriend Haruya
Befriend Yukinaga
Befriend Kaori
Befriend Kuroku&Shiroro
Befriend Shiren
Befriend Takamiya
Befriend Hakuhi
Befriend Natsukage
Befriend Shitara
Befriend Yasune
Befriend Akuta
Befriend Sekiyu
Befriend Miumi
Befriend Nio
Befriend Sakuma
Befriend Kiri
See the Bad End
Begin Chapter 4
Begin Chapter 3
Begin Chapter 2
Find the Cheat Code (bottom-right of Bit World...)
Begin Chapter 1