Full list of all 52 Investigator achievements.
The base game contains 34 achievements, and there is 1 DLC pack containing 18 achievements.
Kill Steve
Find six gnomes in DLC
Do not kill Steve
Get in the face
Complete the tenth level
Burn on a hot plate
Play the guitar
Find the gnome on 10 level
Find the saw room
Complete the ninth level
Complete the eighth level
Complete the seventh level
Make a snowman
Collect five gnomes in the seventh location
Fall through the Ice
Complete the sixth level
4 8 15 16 23 42
You are bitten by a spider at the sixth location
Complete the fifth level
Complete the fourth level
Try to get away from Johnny
Complete the third level
Explore the plane
Do not kill spider
Dial pockets full of garbage
Complete the first level
Find the gnome in the toilet
Kick the ball into the goal
Warmed by the fire
Push the barrel into the water
Find the gnome at the third location
Complete the second level
Kill the spider
Play the game
Find Artifact in "Survivor Update"
Finish "Survivor Update"
Find new shoes
Find the hidden achievement on the fifth level "Survivor Update"
Look where you're going! This is not Assassin Creed "Survivor Update"
Find a can of fuel "Survivor Update"
Find a suitcase with achievements "Survivor Update"
Too slow! "Survivor Update"
The way "Survivor Update"
You were eaten! "Survivor Update"
Find second Artifact in "Survivor Update"
Find five balls in "Survivor Update"
Play "Survivor Update"