Im fucking confused is the grey him "thinking" or the grey him talking in like a "deep voice/serious tone" I mean it seems like he should mention the apocalypse THEN the guys like "what kind of joke on april 1st" etc..etc.. Because if you follow the story it seems like the april fools joke was him slamming his boss on the floor, which no1 in there right mind would assume that as a joke. I hope this whole manga isn't like this.
Edit: Still will enjoy it, just a little less if its super fast like this. Something like The Last Human is a great read in the same aspect.