Goofs

Muriel made potstickers not chicken dumplings.

When Courage got his head stuck in the fence in the flashback, his mother said they had to get him to the vet to get him out. How'd they get that chunk of gate off to take him there?

The veterinarian has been doing his "Dog Breeding in Space" experiment since Courage was a puppy. Wouldn't people have gotten suspicious that dogs continued to disappear at that Veterinary Hospital?

When the vet gives puppy Courage the lollipop while he talks to his parents "in private", it rips his tongue clean off. Yet, in later scenes, he has gotten his tongue back.

When the vet is chasing puppy Courage after discovering him trying to get his parents out of the rocket, his hair and beard suddenly become white; in the next scene, his hair returns to its natural color of gray.

The morning after Courage's night of nightmares, Eustace blows his horn to scare him awake. If you slow it down, you can clearly see Courage begin open his eyes in fear before Eustace even blows the horn.