Here is the full list of all 23 The Innsmouth Case achievements.
Played through all endings
Discovered all of Innsmouth
Wrongdoings have consequences
Mentioned your vegan lifestyle 3 times
Traumatized Evelyn
Dahlia spared your life
Snooped through the Marsh Family records
Pissed Dahlia off to death
Slept with Priscilla
Saved from the stake
Used dirty methods to avoid payment
Discovered fragments from Innsmouth’s history
Snooped through an abandoned hotel room
Wendy found a safe place
Overpowered the gawper
Played a creepy Arcade Game
Found a couple of weird City Hall records
Became friends with Jonah
Seduced Ethel
Slept with a fish creature
Didn’t touch the cube in the lighthouse
Survived a night in the Gilman Hotel
Spent a night with Dahlia