Of the three video-game console manufacturers, Microsoft was the first to embrace online gaming, and its Xbox Live has become essential to anyone who wants to play against faraway competitors. Sony and Nintendo are trying to catch up with, respectively, the PlayStation Network and the Virtual Console.

PSN has more momentum. It's already home to solid multiplayer games like "Warhawk" and "Metal Gear Online," and future projects like "Home," "DC Universe Online" and "MAG" (a 256-player war game) promise to stretch Internet-connected play in innovative ways.

Sony also lets you download games directly to your PS3 hard drive. The library isn't as impressive as Microsoft's or Nintendo's, but there are some gems ("Echochrome," "PixelJunk Monsters") that you can find only on PSN. Each of the three games reviewed here brings some fresh ideas to the network, and may provide some hints of what's in store for PlayStation diehards.

_"Ratchet & Clank Future: Quest for Booty" (Sony, for the PlayStation 3, $15): At the end of last year's "Tools of Destruction," Clank disappeared with a tribe of his fellow robots. As this new chapter begins, Ratchet (the furry half of the duo) discovers that the pirate Captain Darkwater may know where Clank went. Unfortunately, Darkwater is dead, so Ratchet must search for the scurvy seadog's treasure in hopes of finding a clue.

"Quest for Booty" plays like a stripped-down version of its predecessor, leaving out all the side missions and minigames in favor of straight-ahead action. Even Ratchet's impressive arsenal of wacky weapons has been scaled back: For much of the game, his only tool is his trusty wrench. There are still plenty of nifty puzzles and running-and-jumping action, though, so things never slow down.

For a project that's really a stopgap between full-fledged "R&C" adventures, "Quest for Booty" still delivers the brilliant animation and screwball humor we've come to expect from the developers at Insomniac Games. It only takes about three hours to finish, but it's a tasty appetizer until the next main course arrives in 2009. Three stars out of four.

_"PixelJunk Eden" (Sony, for the PlayStation 3, $10): The Kyoto, Japan-based Q-Games has released three very different titles for PSN: the slot-car game "PixelJunk Racers," the strategy game "PixelJunk Monsters," and the uncategorizable "PixelJunk Eden," which looks like no game you've ever seen before.

Each level begins in an underpopulated garden with a minuscule hero who can swing and jump from leaf to leaf. When he swings into a "prowler," it releases pollen, which helps more plants grow. The goal is to grow the plants high enough to reach the prized "Spectra."

The psychedelic visuals and techno soundtrack give "PixelJunk Eden" a trippy vibe, but its controls take some getting used to and may frustrate casual gamers at first. Also frustrating is a very unforgiving timer, which forces you to rush through levels instead of allowing you to admire your gardening skills. Still, the deeper you get into "Eden," the more satisfying it becomes, with challenges that cleverly expand upon the minimalist approach of the early levels. Three stars.

_"Siren: Blood Curse" (Sony, for the PlayStation 3, $15 for four episodes, $40 for 12 episodes): In an interesting experiment in episodic gaming, Sony has retooled the overlooked 2004 title "Siren," chopped it up into a dozen chapters and set them loose on PSN. The graphics aren't much better then they were are the PlayStation 3, but the developers have tightened up the gameplay and added some American characters.

In the first episode, a U.S. camera crew stumbles across a Japanese village populated by zombies, and you briefly assume the role of a college student who's trying to escape from an undead cop. In later episodes you see the events in the village through different characters' eyes _ at times, even through the eyes of the zombies themselves.

It's an effective survival horror adventure, but the episodic structure doesn't help, mainly because the individual chapters take so long to download and install. Also, the early chapters are very short (about 20 minutes), which may dissuade cost-conscious players from downloading the entire run. I'm hoping Sony takes more chances on episodic games, but next time its developers need to build one from scratch. Two stars.

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On the Net:

PlayStation Network: http://www.us.playstation.com/PS3/Network