A healthy gaming diet requires balance.

After a few hours of chain-sawing aliens in "Gears of War," it's good to kick back and play with your Nintendogs for a while. Once you've released your aggressions, why not get in touch with your nurturing side?

Nintendo's long-running "Pokemon" series is all about nurturing — building up an extended family of cute li'l monsters.

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Ironically, the way to make your critters grow is by having them attack other animals; with time you can turn an adorable baby penguin into a ruthless killing machine.

Pokemaniacs probably don't spend much time reflecting on that dichotomy. After all, the game's slogan is "Gotta catch 'em all," and it's the collecting impulse that makes it addictive.

But if the formula was that simple it would be easy to duplicate — and so far, no other creature-collecting game has been able to reach the heights of "Pokemon."

— "Pokemon Diamond"/"Pokemon Pearl" (Nintendo, for the DS, $34.99 each): The first true "Pokemon" title for the DS comes in two flavors; the only difference is that some monsters appear only in "Diamond" or "Pearl."

Either package delivers more than 100 new, delightfully conceived creatures, from the "turtwig," a turtle with a twig growing out of its head, to the "chimchar," a chimpanzee with a flaming tail.

After deciding to play as a boy or a girl, you're introduced to Professor Rowan, a scientist who's cataloging native wildlife.

As you run around the land of Sinnoh collecting specimens, you encounter rival trainers who want to pit their Pokemon against yours. Eventually you learn of a threat from Team Galactic, a villainous, pseudo-military group.

While the plot is overly familiar, there are some nice new touches.

Early on you get the "poketch," a digital watch that can be juiced up with a variety of fun devices. You can also trade with and battle players from all over the world through Nintendo's Wi-Fi service.

With a long main story and a deep selection of side challenges, "Pokemon Diamond" (or "Pearl") is one of the most robust games on the DS.

Three-and-a-half stars out of four.

— "Spectrobes" (Disney, for the DS, $29.99): Only one thing can stop the Krawl, a race of galaxy-devouring aliens.

Unfortunately, the spectrobes — our potential saviors — have been hibernating for centuries, so your job is to dig them up and whip them back into fighting shape. Once you have recruited spectrobes, you'll have to fight the Krawl.

"Spectrobes" has a unique fighting mechanism: You and your two creatures move around as one, and you attack the enemies using the DS' top trigger buttons. It's a noble attempt at a new way to fight, but it feels completely unnatural.

With dozens of creatures to find and train, "Spectrobes" is clearly Disney's attempt to create a "Pokemon"-like franchise.

But the monsters you'll discover — a three-headed dragon, a squirrel whose ears can be used as wings — aren't as clever or as cute as Nintendo's, and the effort you have to go through to find and excavate them is tedious.

Most players will lose patience with "Spectrobes" long before they get anywhere near having a big collection.

Two stars.

— "Custom Robo Arena" (Nintendo, for the DS, $34.99): You're presented with your own robot right at the beginning of "Custom Robo Arena." The trick is to pimp your bot with some of the 200-plus guns, rockets, shields and other parts in preparation for duels against other players.

The duels are the most entertaining part of "Custom Robo." You meet your opponent on a floating, square platform and have guns, rockets, bombs and various other devices to bring him down; experience and money earned help you upgrade to new gear.

You'll need those upgrades, because your foes get tough fast.

The plot of "Custom Robo" is predictable and even a little bit annoying, but it's really fun to try out all the different combinations of equipment.

Two-and-a-half stars.