Here is the full list of all 34 Pawn achievements.
Nail the Free Time Investigation events
Do your job, more or less...
Botch the investigation
Get the good ending
Interrogate Kojima
Interrogate Umehara
Pick the wrong weakness
Interrogate Aonuma
Interrogate Higuchi
Cleared the fifth chapter
Join your fellow teachers and paint the town red
Kick back on your couch, all by yourself
Be a man
Taste Noriko's sushis
Get any bad ending
Follow the chief to a wet place...
Interrogate Tanabe
Interrogate Taguchi
Interrogate Okawa
Cleared the fourth chapter
Interrogate Higashiyama
Interrogate Ichiyusai
Interrogate Hiroyuki
Cleared the third chapter
Interrogate Hamacho
Interrogate Shimada
Interrogate Satoya
Cleared the second chapter
Cleared the first chapter
Cleared the prologue