Here is the full list of all 9 The Most Boring Game Ever achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
500! Keep Going!
420! Grass Lover!
Welcome to number 100.
1! Welcome to The Most Boring Game Ever no turning back now.
666! The Devil's number!
1000!? How are you finding this fun?
10,000...Are you ok? Do you need help?
100,000. You still having fun? I hope so.
500,000...YOU ARE... A GOD