Here is the full list of all 9 Siren Head: The Siren's Forest achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Reached The First Chapter
Reached The Second Chapter
Reached The Third Chapter
Reached The Fourth Chapter
Horror games should be played in the dark!
Turn Around And Try A Different Path.
You Managed To Die, Try And Run Faster Next Time
That Wasn't The correct Way!
You Reached The End Of The Game! Thank You So Much For Playing The Game