Here is the full list of all 14 Welcome To... Chichester 2 - there are Part III : NightFall Demo achievements.
Starting a new game
Enter in a new name
Completed the prologue
Complete the game as a male protagonist
Complete the game as a female protagonist
Find the first bad ending
Find the last bad ending
Complete Year 4 Secret Scene
Complete the recap story
Completed WTC 2 - Part I
Completed WTC 2 - Part II
Complete Prologue Secret Scene