The ending card with the name of the manga sounds like it's messing with us. "Haha, you're all gonna die eventually. Have a nice weekend!"
Lol, that aside, this is a sad-ish but also kind of poignant story. Very short, but the concept is there. I'm glad he was happy at the end. I've always found stories where the world ends abruptly to be kind of peaceful. We'd all go out together, and there's a since of calm that comes from that. But, obviously, it'd be nice if we could just live freely without the world ending, lol.
Have a Nice Weekend