Here is the full list of all 8 Pivvot achievements.
In Looper mode, complete five loops in a row without stopping
Complete the Voyage mode without a single death
You are a masochist!
Complete the Expert Voyage mode without a single death
Get to Wave 5 in Looper mode while only turning in a single direction
Survive for 100 seconds in Random Endless
Survive for 100 seconds in Random Expert Endless
Survive for 100 seconds in Berserk