Here is the full list of all 12 Forest Grove achievements.
Found a way into the Nanodeck
Found Max's secret area
Found Zooey's secret playroom
Played the piano and opened a secret closet
Set the time on the grandfather clock correctly
Aligned all the hovercams in the house and have the report desk unlocked
Listened to all the audio fragments in the house
Found some incriminating phone/laptop messages
Submitted your first case report
Solved the case
Discovered how dearly Max misses his wife, Rebecca
Reached the highest grades as an investigator