Help with a movie ending? [end game spoilers]

I just watched the ending to Final Fantasy Type 0, and it shows them
*spoilers*
All happy and laughing, then Rem comes in and they are all dead.
It got me thinking about a movie..
I could be thinking of just a basic theme, but i am pretty sure i am thinking of a particular movie.

Its very dramatic at the end and the whole movie they have done things to save the world or the battle or whatever obstacle, and then in a line or two, someone just says something along the lines of "im sorry" or "it didnt work" and then they all die, to put it bluntly.
It could be a post apocalyptic themed movie, or something to do with a bomb.,. So if that sounds like any movie you know, that has been well made, i think in the last 4 years at the most. It is a recent movie, but just in case...
So the tension is high and they are about to save everyone and then someone just says it wont work and it ends abruptly, or you see an explosion, or just really suddenly, no sad pan of the city or anythin.

Thank you so much!