Sadly the PDX only works with the simulator (which comes with the free Playdate SDK), or on an actual PlayDate.
Thanks, that's really helpful! Based on that error report, it may be that no-one has actually had all the children die since we released the "full" version of the game, lol. Perhaps the whole ending is broken.
EDIT: Ugh, looks like a recent update which enabled easy save-games causes a crash when converted using Pulpmill like this game is. I'll look into a fix.