Little Nightmares has 22 achievements worth 2200 gamerscore

Little Lost Things 0 Kindness will be your undoing!	50
Rascal 0 Little vandal, little beast, The Maw will punish you at the feast.	50
Light Up Your life 0 Not all lights can be trusted, but these should be quite safe!	50
The Prison 0 Look how the canary has flown its cage!	50
The Lair 0 Little lost things sometimes find their way home.	50
The Kitchen 0 The Chefs will miss you!	50
The Guest Area 0 Little fox among hungry wolves!	50
The Lady's Quarters 0 A storm is coming. That coat should come in useful.	50
Hard to the Core 0 What’s different about you? Why are you so brave?	200

Secret Achievements

Kitchen Hand 0 The recipe is complete, the feast will be divine.	150
Highly Sprung 0 You'd jump even higher if you knew what slept there!	50
Elusive 0 Hey sneaky rat, how do you keep slipping away?	50
Six's Song 0 So many keys, yet none to unlock your cage!	150

Little Nightmares - The Depths

There are 3 achievements with a total of 400 points.

So Close 0 You'll do better next time.	50
Not Alone 0 What's new with you?	200

Secret Achievements

Fun and Games Ahead 0 Play nicely, no pulling hair.

150

Little Nightmares - The Hideaway

There are 3 achievements with a total of 400 points.

End in Sight 0 The final stretch will be largely uneventful.	50
Is Anybody Out There? 0 I wish I could visit you there.	150

Secret Achievements

Ashes in The Maw 0 Are you proud of yourself?

200

Little Nightmares - The Residence

There are 3 achievements with a total of 400 points.

We'll Meet Again 0 The final chapter is written.	50
I'm Losing You 0 I'll be out of reach for a while.	150

Secret Achievements

Ashes to Ashes 0 Who knows what secrets they hold?

200