It took me a few hours but was able to reach the ending. Both path share the same answer until mid of the game when Olivia reach you in the lab, select the choice "I look happy", "respond calm" then "Do you know about my dreams?". To reach the dream ending from there, select the following choice:
"Comment on her appearance."
"Tease her lightly."
"doesn't matter!"
For the last choice, there is 4 "Yes" choice, the third is the right one.