Here is the full list of all 21 Richard & Alice achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
You used a child's toy to escape from the basement.
You encouraged Alice to begin opening up.
You gave Alice the guided tour.
You moved into a nice new house. Sort of.
You used cleaning supplies incorrectly and got very upset.
You took Barney to his dad's grave. Or did you?
You called for help… but no-one came.
You desecrated a church, but don't feel too guilty.
You escaped from certain death, irresponsibly.
You know what you did.
You escaped from prison, and uncovered the truth.
You went off to uncharted territory.
You parted ways... amicably.
But is it justice, or revenge?
You made your final decision.
You finally understand each other.
You defied death and retrieved the mysterious box.
You found and read all the documents.
You watched the highly accurate TV adaptation of Analogue: A Hate Story.
You gave Barney a keepsake.
You talked to Alice about your family... again.