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