Here is the full list of all 15 Amigdala achievements.
Finish Chapter one
Hear 12 audio files
Collects 50 batteries
Read 25 documents
Hear 8 audio files
Collects 30 batteries
Read 15 documents
Hear 4 audio files
Collects 10 batteries
Read 5 documents
Start new game
Finish Chapter two
Finish Chapter three
Finish Chapter four
"Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn"