[yolin.shana]

Spoiler for luke and asch:

Well, it's hard to say. They left the interpretation up to the players.
If you want it to be Luke's mind in their fused bodies, then it is. Same if you want the one to return to be Asch. You could also believe that both return safely (<- my personnal choice).

About the harshness: the scene on the Tartarus was the same as in the game, but they made Jade and Anise in the anime nicer to Luke right after he cut his hair. They also changed Nat's reaction, this time the other way round =(
And Asch is much more nicer, less angry, and less contradictory than he was in the game.
Apart from that it's more or less the same.