Here is the full list of all 11 This is the Zodiac Speaking achievements worth 1,000 gamerscore.
Set the chronology of events
Unlock the first hologram
Meet the Zodiac for the first time
Open the safe with a code
Drop the puppet in the shed
Get caught by the Zodiac
Complete a level without being caught by the Zodiac
Complete the entire game without being caught by the Zodiac
Watch all cutscenes
Collect all Journal Clues
Finish the game