Here is the full list of all 9 Runeous: Part One achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Make Lene Unhappy
You've reached the very end that end could be!
Make Col Unhappy
Finish the Game
Embrace the fear!
Unlock the power of thought
Meet a mysterious stranger
Make Lene Happy
Encounter a monster and beat it!