Hey dev. So I'm trying to get all endings and the only ending left I have is Yoshiki being dead. When I let Yoshiki die in the science lab and let the others live, the game shows Yoshiki dead but in the ending list, the star is unlit so is that a bug? Here's the video:
I FIGURED IT OUT! So the save file should be tracking the deaths properly, but I messed up on the order of the characters in the ending screen. So the game knows you've gotten the ending where Yoshiki is the only dead character, but it's listing as though you have the ending where only Ayumi dies in its place. So the ending you're ACTUALLY missing is the one where Ayumi is the only death.
I'll make a quick patch to fix this, but you should be able to just kill Ayumi in the Science Lab and complete that ending list. Sorry for the confusion, and again, thank you for bringing this to my attention! Feedback like this helps us solo devs improve our games!