Here is the full list of all 20 There Was A Caveman achievements.
Die 500 times!
Die 250 times.
Have 100 skulls.
Slay 100 turtles.
Complete guts without dying!
Complete snow plains without dying.
Complete afterlife without dying.
Complete underwater without dying.
Complete forest without dying.
Complete caves without dying.
I quickly forget..
Complete the guts
You found your love!
Die 100 times.
Complete the snow plains
Complete the afterlife
Complete the underwater area
Complete the forest
Die 10 times.
Complete the caves