Here is the full list of all 26 Cloud Chamber achievements.
Open the node How The Mighty in Chapter 10
Earn 10 "Best comment" badges
Open the node Ghost Circle in Chapter 9
Open the node Run! in Chapter 8
Open the node Message In A Bottle Music in Chapter 7
Open the node The Family Secret in Chapter 6
Open the node It's A Big Universe in Chapter 5
Like 50 posts or comments
Open the node Sound Of The Sun in Chapter 4
Earn 10 "Best post" badges
Open the node Revelation in Chapter 10
Open the node On The Edge in Chapter 8
Open the node Perspective in Chapter 8
Open the node Visionary Music in Chapter 7
Open the node Auditive Algebra in Chapter 6
Open the node Brilliant Minds in Chapter 5
Open the node A New Plan in Chapter 4
Open the node In Friedrichshafen in Chapter 3
Earn a "Best comment" badge
Open the node Did You Kill Your Wife? in Chapter 3
Open the node 100 Bilion Stars in Chapter 2
Open the node Preparations in Chapter 1
Like a post or comment
Earn a "Best post" badge
Open the node Ingrid Petersen in Chapter 2
Open the node You Are About To Enter in Chapter 1