I liked the premise. It seemed a little bit flaky. (It wouldn't start from within the Itch app. I think it crashed on me once.) I think it's missing some way to keep score. It also feels like just pushing off the inevitable as there's no indication that they do anything but move offscreen to all return in number. (Maybe that's not what's happening, but could use some animation to be clearer?)
As you say in the description, though, "This is quite regrettable," and I think the game does a great job with the theme. I think it is good enough to get the message across. :)