I liked it!

By the way, you might be interested in a similar story by Keiichi Sigsawa in Kino's Journey, The Beautiful World, 2000, v. 1.

Two nations have made peace with each other by organizing a friendly competition, after a hundred years of ever more deadly warfare. People happily prepare for "war" each year, which now means the competition.

What's the competition? That's where the story turns rather dark. They have advanced technology. They fly over to a third country with primitive technology, and start bombarding the buildings and dropping anything that moves, until the time limit. Then neutral judges count the bodies of the dead. Whichever country has produced the most bodies "wins" the "war" . . . and hosts a festival. The bodies are meanwhile strewn outside the city wall.

The people of the two countries seem to think this is better than having their own war, because, when they fought in the past, many on each side died in that conflict. Now, none, meanwhile those in the third country cannot resist the invaders. The narrator, being only one person, observing it, can't do anthing to stop it.