Here is the full list of all 35 Little Nightmares II achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
It's all over now
It would be cliché to collect them all
Life in the big city is all over
Are you sure you don't need any further... treatments?
Better to be safe than sorry
Best days of our short, terrible life
You never know when you need protection from the elements
Nature is a terrifying thing
It's not murder if they're bad people... is it?
What did you expect to see in there?
Your life is now free of challenges. Congratulations
Nothing of us remains anywhere. Bravo!
Hats are very important to some people
Not today!
Perfect! It's so... you!
Hold tight and we'll be just fine
There, you'll be much warmer now
Movie night on the ward - all taken care of!
Plenty of snacks for a growing boy
I see through you...
Some holes are more picky than others
It's crueller to let him live
Nothing of us remains in the hospital
You punctuated someone's day. Maybe they'll notice!
Hello, have we met?
Nothing of us remains in the pale city
Unorthodox, but they all count!
My, what a curious song you play!
Creative, efficient, brutal. Top of the class!
Rebellion at its finest!
Nothing of us remains at the school
Nothing of us remains in the wilderness
Relax, she heard you!
Any other last requests?
Tempting, so tempting...