You were able to save Dogday and defeat Catnap. Dogday watched as Catnap got stabbed and dragged by the prototype into the roof. Dogday didn't move for minutes, and wouldn't speak. He just kept staring at the scene.

After killing Catnap and getting Dogday out of that stupid room, you chose to help Dogday rebuild the other critters so he wouldn't be alone. But everything felt strange about Dogday. He wouldn't speak, his tail wouldn't wag, and he wasn't as happy.

He clearly missed his previous best friend