Its barks sound just enough like your name, but just different enough, that you question what you heard.
Then, after you choose to exit the demo, the virtual puppy goes back into its cage, whimpering. The last thing you see before you close the 3DS lid is your puppy's paw up against the screen. Occasionally you'll receive a note via SpotPass telling you that the little scamp still looks out the window whenever a car the same model as yours drives by.
We didn't design the real demo.