THE GOOD:Lots of toys and accessories to collect
Cute breeds
Amazing graphics
Lots of things to do
THE BAD:
A bit repetitive
Some items are quite rare, and hard to obtain
SUMMARY:
You first start out at the kennel with £1000, and you choose from the six available breeds. You bring it home, and it will be nervous of its surroundings. Pet it a little, then you name it, then your life begins!
The sounds are very realistic, like you're actually there. Much like the graphics, which make the puppies look even cuter. There are lots of accessories to accessorize them with, so for all you fashionistas out there, dress up your doggy to match you! Like what I said, lots of accessories.
If you're more a sporty person, enter disc and agility trials and play football with doggy (yep, you read that right), or if you're a talented person who is really smart or musical then teach your dog tricks for obedience trials and play the keyboard and they'll sing with you! So you have no excuse to not go and buy it and love it. 
These dogs are really life-like, they get tired, annoyed, but also happy and excited, and maybe even a little flirty with other dogs. But, the point is to smother them in love and care.
There is literally hundreds of things to do in the game. Feed it, wash it, brush it, walk it, play with it, teach it, accessorize it, phew! And more... so does that make you wanna buy it? No?! Damn, you're stubborn! :L Here's one last cool feature: Bark mode. If your friends have Nintendogs, you can meet them and trade items with them, AND if it's your first time connecting with them, if they have a dog that's not in your kennel then you'll be able to buy that breed!
The worst thing is possibly the mic. At the start of the game when you first teach your dog its name, it could literally take FOREVER! And it's a bit strange to see someone talking to their DS, isn't it? So you should really only use this feature at a private place like your room. Or the bathroom.
Another bad thing is how it's sometimes hard to obtain things called Trainer Points. The more of these you have, the more breeds and items you can get. The best way to get these is competitions. You get 500 points if you win one, which is a lot. But, what happens when you only have one or two dogs? Not a lot.
Possibly, this game is better than all of the other simulation pets games put together. Like the title says, your own personal puppy. No one can mess with him either, unless they steal your game xD I would definitely recommend this game to all DS players, young and old.
This game is great, I'd rate it a solid 4.7 out of 5