Nintendogs

Nintendogs was the early Killer App of the Nintendo DS, especially popular with children and young women. You get to look after three puppies which you can feed, walk, play with and bathe. You can teach it to do tricks in response to your real voice, using the DS microphone, and enter it into contests to win virtual prizes.

Unlike Tamagotchi and similar virtual pets, a Nintendog will not die, get sick, or even age beyond puppyhood. Even if the game is neglected for an extended period of time, the worst that happens is that the dog may temporarily "run away."

Nintendogs + Cats was later released for the 3DS. As you may have guessed, it adds kittens as virtual pets you can keep.

This game provides examples of:

 * Anti Poop Socking: When you return from a walk after playing for half an hour, the game will suggest you take a break. If you play for an hour, a warning will come up urging you to save.
 * Author Appeal
 * Augmented Reality: Nintendogs + Cats has an AR mode.
 * Casual Video Game
 * Cats Are Superior: Inverted. Dogs can earn their keep in Nintendogs + Cats by winning competitions and picking up gifts while walking. Cats mostly hang around the house all day, but if you leave them alone for long enough (30-45 minutes), they will go outside and bring back gifts. Even so, dogs can earn you money faster than cats.
 * Cloudcuckoolander: Contest commentator Archie Hubbs.
 * The Computer Is a Cheating Bastard: It's notably hard to win the hardest levels of the frisbee competitions, due to the fact that you have to have a perfect lucky stylus-slide for a toss, and sometimes you just get unlucky and your dog drops it. The other dogs almost never fail as the levels get harder, and they can "accidentally" walk through your dog, pushing it aside and causing it to not catch the frisbee.
 * Cute Kitten: As stated above, the 3DS sequel has them.
 * Deathbringer the Adorable: If you want to, of course.
 * Everythings Better With Sparkles: Your puppies return from being bathed/brushed to beautiful with sparkles for a few seconds. Sparkles also show up occasionally when you pet them.
 * Exactly What It Says On the Tin: Nintendogs, a Nintendo game about dogs. Nintendogs + Cats, a sequel to said game with kittens.
 * Extreme Omnivore: You can feed your puppy treats meant for the cats (and vice versa), but they obviously won't enjoy it as much as a cat would (same goes for the cats eating dog treats).
 * Guilt Based Gaming
 * Gotta Catch Them All: Including the rare Jack Russell terrier.
 * In the sequel the Jack Russel has lost its rarity, and it's now a Robot Dog.
 * Idea Bulb
 * An Interior Designer Is You
 * Killer App
 * Luck Based Mission: In Nintendogs + Cats while walking your dog, there are occasionally rows of safety cones you can optionally zig-zag through to get a present. If a bag of trash, puddle, fire hydrant or mailbox is randomly generated at the end of a row of safety cones, forget about that present at the end, because your dog will forget all about the cones and happily dash towards the taboo, and you can't re-do it because you can't walk backwards.
 * Your dog will occasionally decide that it would be a perfect time for a bathroom break when going through the cones, it'll often move one of the cones, denying you the present as well.
 * Mushroom Samba: Feed your kitten the Chicken Jerky, which is sprinkled with catnip according to the description, and your kitty will spaz out for a few seconds.
 * Not Allowed to Grow Up: Your dog will forever stay a prepubescent puppy.
 * Infant Immortality.
 * Ratchet Scrolling: You can't walk backwards when walking your dog in Nintendogs + Cats. Passed someone else walking their dog? A place you were wanting to visit all day? A present? Too bad, you can't go backwards, not even an inch. This is probably implemented to make dog walks have a finite length, but it can still be annoying when you walk an INCH too far and miss something.
 * Serious Business
 * Shout Out: You can get a Mario or Luigi hat for your puppy. In addition, you can unlock radio-controlled Mario Karts that you can drive around. There's also a ? Block.
 * Spiritual Successor: Could be considered this to the Petz series of games.
 * Urban Legend of Zelda: There have been plenty of hoaxes about breeding the puppies. They tend to include having 9999 trainer points and having dogs of "a certain nature". Knowing the fandom and target audience, people believe it.
 * There's also the infamous "Nintencats" rumor which involves Nintendo creating full, playable, counterparts involving cats but not releasing them since a game about kittens wouldn't sell (though, as noted, they did eventually add cats to the series...).
 * Vendor Trash: Your dogs can find things on walks which you can later sell. Along with ordinary useful stuff like accessories, they can find things like empty juice boxes, sticks, and broken disposable cameras. At the other end of the scale, there's fallen meteors and expensive vases which fetch quite a lot of money.
 * Videogame Caring Potential: You can be the sweetest owner ever. Or...
 * Video Game Cruelty Potential: You can torture the little dogs.
 * Wizard Needs Food Badly: Justified being that they're puppies, most likely less then six months old.