The dog is a descendant of Muttley, what with the snickering.
By extension, the player is Dick Dastardly. Next hunt, the hunter took a different dog.
And he
was Poochy. The Duck Hunt dog's mocking laughter may be completely justified.
Why does the dog laugh? To poke fun at you? To encourage you? Because he can't help himself? There is only one reason that the dog laughs at you, and it's perhaps one of the earliest examples of this phenomenon: The dog was telling you to git gud. The ducks are deaf
Ten ducks flying out one at a time despite a dog invading their nests and bullets flying around? Yeah no. Dog barks and sound of bullets whizzing by would make all the ducks fly out of there at once. Your in-game score is an unidentified currency
After the game is over, the hunter sells his haul of ducks to a butcher, and the score is how much money he got for them, though we're not sure which currency it's in.