Something funny about the Duck Hunt dog is that I think every time someone tries to draw or interpret the character, they get fixated on one specific sprite out of 3
The Vs. Duck Hunt flyer (perhaps by proxy of the Vs. Duck Hunt bonus sprites doing so as well), is clearly based on the "hold a duck" sprite - very silly character. In the case of Vs. Duck Hunt, the dog is portrayed as bipedal too since it stands on its hind legs in the grass.
Most fan renditions of the character, at least until Smash 3DS came out, were based on the laughing sprite alone, a canine trollface. Also typically bipedal
and then finally the Smash design fixates on the otherwise least drawn-from animation - the walking into bushes animation, depicting them with dopey eyes and near-constant quadrupedalism. He's a bit more Disney-like compared to his origins as a seemingly Hanna-Barbera inspired character
Ironically, of all the DH designs - official or otherwise - the one that feels the most balanced between the original sprites is actually You Cannot Beat Us - it's obviously an unfaithful adaptation of the character (which I would argue to be true of the Smash version as well), but it's the only one I think encapsulates all 3 sprites at the same time. His pupils are a little low and squash, kinda evoking the walking sprite; the scary attitude and chainsmoker voice is at least adjacent to the laugh (and that sprite is obviously the reason for this portrayal); and his mouth is shown open but not with a outstretched tongue or teeth; as well as having open eyelids; like the holding sprite.