Here is the full list of all 38 World of One achievements.
One small step for man…
Now she won't perish
Knife switches are fun!
When the fireworks flash, no one looks at the starry sky
In the event that it does speak, we urge you to disregard its advice
It worked!
Tesla is proud of you!
It's alive!
Morning Star
Flawless victory!
Completed the first act without dying
Cemetery Caretaker
If you go left, you’ll find monsters
If you go right, you’ll fall into a trap
Now you’ve done it...
…or weakness?
...or brutality?
...that takes away the sin of the world
He accepts your offering
Monster kill!
Completed the second act without dying
Let's play hide and seek!
The light will show you the way
Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn!
Pollice compresso favor iudicabatur
Don't lose your head
Killing spree!
Completed the third act without dying
Godlike!
Complete the game without dying more than 7 times
Unfinished Symphony
There's nothing left of me
I found it
I just need to find it
Serves you right!
Learned the secrets of the Cosmos
Completed the game on Hardcore mode