Here is the full list of all 28 Brain Break achievements.
You have completed Level 20
Finally! You have passed all the levels!
You have completed Level 19
You have completed Level 18
You have completed Level 17
You have completed Level 16
You have completed Level 15
You have completed 15 levels
You have completed Level 14
You played the game for 2 hours
You have completed Level 13
You have completed Level 12
You have completed Level 11
You played the game for 3 hours
You have completed Level 10
You have completed 10 levels
You have completed Level 9
You have completed Level 8
You have completed Level 7
You have completed Level 6
You played the game for 1 hour
You have completed Level 5
You have completed 5 levels
You have completed Level 4
You have completed Level 3
You have completed Level 2
You have completed Level 1
This is just the beginning!