The ending of the game. Imagine the ending to Final Fantasy X, except worse. If Rush's willingness to sacrifice himself to destroy all Remnants to save the world and the revelation that he is one of them didn't have you bawling, and the voice acting didn't do it either, you have a heart of stone.
The others' reactions to his death are nothing short of heartbreaking. Rush is all but willing to die if it meant that Irina is safe, but it's clear that Irina doesn't want the same as she tries to stop Rush, with David holding her back. And it's even obvious that David is just as grief-stricken over Rush's sacrifice, otherwise he wouldn't cry out his name the way he did.
The sadness of the ending is made even worse by the final scene of Irina standing with their parents on the same cliff that she and Rush did in the beginning of the game... without Rush.
On the brighter side, the after-credits scene turns the Downer Ending into a Bittersweet Ending. Like the ending to FFX, it's revealed he might just come back. Cue happy tears instead.
Also, Emma Honeywell II. At first it seems like YMMV because of the timing in her appearance, but then you realize that Emma had been waiting for her to come back from her journey and never got to see her. Emmy showed up minutes too late.
