Here is the full list of all 12 Vex achievements.
The base game contains 11 achievements, and there is 1 DLC pack containing 1 achievements.
Obliterate 15 enemies using God mode
Die from colliding with a Glide.
Kill 50 Patrol enemies
Kill 25 Patrol enemies
Complete the Glacium Dimension
Complete the Ignis Dimension
Kill 10 Patrol Enemies
Complete the Pura Dimension
Complete the Quanta Dimension
Unlock the Iris Dimension
Unlock all 4 bonus levels
Complete the Iris Dimension