Thank you so much for playing the game, and so thoroughly, too! It makes me happy that you enjoyed it so much! I need to go through myself and make sure that I didn't accidentally program something incorrectly, but it is likely in the section after Riley chooses to bring the deer home or not. There are different unlockable sprites in the following sections:
Sacrifice -> Try to bring home the deer
Sacrifice -> Don't try to bring home the deer
Compliance
Mercy -> Bring home the deer
Mercy -> Don't bring home the deer
If you go through these configurations and are still missing a sprite, please let me know. I meant to try this earlier myself to see if I had a bug but I didn't have the time. Apologies for the delay!