Here is the full list of all 16 Reveal achievements.
Start your journey
Travel for the first time
Reach the first puzzle
Reach the second puzzle
Reach the third puzzle
Return to the forest for the first time
Reach the fourth puzzle
Reach the fifth puzzle
Reach the sixth puzzle
Return to the forest for the second time
Reach the seventh puzzle
Reach the eighth puzzle
Reach the ninth puzzle
Return to the forest for the third time
Drain power from a gate
Reveal the truth