The gameplay in Nintendogs is an advanced pet simulator. You begin by "adopting" a puppy from the kennel, after which you must care for it by giving it food and water and ensuring it is kept clean. You can also play various games with your pup and teach it tricks. There is also the option to enter your virtual pup in virtual competitions and to take it for a walk around the virtual neighbourhood where you can find or buy various cool items.
You can "own" eight pups at once, however only three of them can be with you at any one time. The others must be left at the dog hotel.
Unlike some other virtual pet simulators the puppies in Nintendogs remain puppies. They do not grow old, breed or die. However if not properly cared for they may "run away" - fortuntely they usually return soon.
Nintendogs makes good use of Nintendo DS special features such as the touch screen, sound and music. It's also possible to use the microphone to record your voice and train your pup to recognise its name and respond to your spoken commands.
"Bark Mode" uses the wireless capabilities of the DS to allow two Nintendogs owners to interact. Players can give each other gifts and let their pups play together.
Some people call the game Nintendogz, presumably by analogy to the famous PC virtual pets Dogz, however the two are unrelated.