Here is the full list of all 16 NOSTOI achievements.
Complete "Tutorial" on Easy Difficulty
Complete "Tutorial" on Medium Difficulty
Complete "Tutorial" on Hard Difficulty
Complete "Doll House" on Easy Difficulty
Complete "Doll House" on Medium Difficulty
Complete "Doll House" on Hard Difficulty
Complete "Come, Spring, Come" on Easy Difficulty
Complete "Come, Spring, Come" on Medium Difficulty
Complete "Come, Spring, Come" on Hard Difficulty
Complete "Mandela Effect" on Easy Difficulty
Complete "Mandela Effect" on Medium Difficulty
Complete "Mandela Effect" on Hard Difficulty
Complete "New Born" on Easy Difficulty
Complete "New Born" on Medium Difficulty
Complete "New Born" on Hard Difficulty
Complete the game