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