As in the original, Dogz 2 presents you with an alternative to having a real dog. You start raising your Dogz as puppies and watch them grow up into adults. You can play with them, scold them, feed and water them, and much more. If you're not a good master, your Dogz will get mad at you and run away.
There are three separate areas in Dogz II and Catz II:
The Adoption Center - This is where the player selects and names their dog. There is also the option of connecting to the Online Adoption Centre to see what new breeds are available and downloading them
The Playpen - this is the main area, it's where the player plays with their dogs, feeds them etc. They can also choose to release their pet from the playpen and have them running around on the desktop area.
The Toybox - as the name implies this is where the player can exchange toys and things on the playpen shelves for new items or old favourites. They can also connect to the Online Centre and download new items
The game's documentation lists the following as being the key features of both Dogz II (and Catz II too):
Multiple Character Interaction: Two pets cats and/or dogs in any combination can be out at once and play together. The manual goes on to list a load of things they can do to/with each other, breeding is not one of them.
Adding New Content: New breeds and toys are/were made available on the game's website
Customizable Interface: This sounds more that it really is, basically they say that being able to stock the playpen shelves with different items is a feature
Improved look: The dogs and cats are, and this is a direct quote "more expressive than ever before and are true real-world breeds."
Adopt Multiple Pets: The key point about having multiple pets is that even if the player adopts, say, two great danes the dogs will be unique because no pets are exactly alike
Improved Training: the big thing here is that both positive and negative reinforcement affects the pets behaviour
A screen saver with two different modes, one which has the pet(s) romping around the screen and the other shoing the in-game pet photos as a slide show
Old Pets: A nice touch is being able to import pets from Catz 1.0 and Dogz 1.0 so that they don't have to be abandoned
Copy a Pet: This feature that allows the player to copy their pet so that they can, and here comes another direct quote, "post them on the Web for others to play with or take your Petz to a friend's computer to play."