Sony has often won big by thinking small. Portable gizmos such as the Walkman, the Discman and the Handicam helped make this company the consumer electronics power it is today. But until now, it hasn’t tried to run that play with its most successful product of the past decade, the PlayStation line of video-game machines.

That changes Thursday, when Sony introduces the PlayStation Portable — PSP for short. This $250 device is Sony’s answer to Nintendo’s Game Boy and DS handhelds. It also represents yet another try by Sony to get into the portable-media market Apple’s iPod owns.

Rob Pegoraro says the $250 Sony PlayStation Portable is a ‘peerless’ gaming machine, ‘combining sharp graphics, deep game play and easy online connectivity.’ (Julia Ewan - The Washington Post)

The PSP does only one of those jobs well, and you can probably guess which one. As a portable game machine, it’s a peerless piece of work, combining sharp graphics, deep game play and easy online connectivity. As a multimedia gadget, however, it’s a dud.

The PSP’s sleek appearance backs up its gaming orientation. This booklet-sized device — 6 5/8 inches by 2 7/8 inches by 15/16 inches, weighing 11 ounces with headphones and remote control — carries a similar layout of buttons to that of a PlayStation 2 controller, plus a sharp, wide-format color display. At about 4 1/4 inches wide, with a 480-by-272 resolution, it’s larger than other game players’ displays and almost as sharp as those on handheld organizers.

The sum of these parts looks just different enough from other portable widgets — and cool enough in its own right — to draw reactions from passerby that range from intrigued to awestruck.

The PSP’s breakthrough feature, however, can’t be seen from outside. Its WiFi receiver allows PSPs to link up for peer-to-peer wireless gaming or, if within range of a separate WiFi access point, competition across the Internet. That second option is absent from the PSP’s chief competitor, Nintendo’s $150 DS. (Web access would have been a pleasant bonus but there is no browser available on the PSP.)

Setting up a PSP for Internet game play is harder than necessary, thanks to Sony’s awkward interface for entering the lengthy alphanumeric encryption key most WiFi access points require.

Otherwise, though, multiplayer mayhem on the PSP is laughably simple. Select “multiplayer” from a game’s menu, choose between local or Internet-wide contests (in a fit of jargon, the PSP calls them “ad hoc” and “infrastructure”), then wait for opponents to show up.

In The Post’s newsroom, two PSPs joined the same game in seconds and maintained the connection up to about 110 feet away. Two Internet-hosted games were almost as quick to set up and showed no signs of lag, the slow response time that can gum up online games.

You can also play PSP titles solo, of course, but it’s just more fun to compete against other people. You don’t get the same sublime sense of satisfaction when the car you incinerate with a hail of missiles is driven by the computer instead of your co-worker.

Gaming novices may find the PSP’s multiple controls a lot to handle. It offers two four-way arrays of buttons to operate with your left and right thumbs, left and right switches to work with your index fingers and an “analog stick” that also falls under your left thumb — and which can cramp up your hand.

Instead of CDs or DVDs, the PSP uses a new, smaller format that Sony has optimistically christened the Universal Media Disc (UMD). These 2 1/2-inch-wide discs store 1.8 gigabytes of data, far more than the flash-memory cards used in other handhelds. (One unpleasant side effect: lengthy waits for games to load, up to a minute in my tests.)

Rob Pegoraro says the $250 Sony PlayStation Portable is a ‘peerless’ gaming machine, ‘combining sharp graphics, deep game play and easy online connectivity.’ (Julia Ewan - The Washington Post)

That kind of storage allows PSP titles to offer much of the depth and detail of games made for the PS2, Nintendo’s GameCube and Microsoft’s Xbox. PSP sports simulations, for instance, let you build teams by drafting and trading players, instead of just playing games with a fixed roster.

Sony says 24 games will be available initially, at $40 or $50 each. (See the related story below for an evaluation of this batch of titles.)

A rechargeable, replaceable battery powers the PSP; it ran for about 4 1/2 hours with WiFi on.

If Sony had quit there, it would have had an unambiguous winner. But it fell flat in trying to turn the PSP into a media machine that plays and displays movies, music and photos.

In this role, the PSP is the prisoner of its own formats. Movies must be bought or rented on UMDs, which can neither be played or viewed on any other devices. Only 22 titles have been announced so far; even discounted off their $20 list prices, these constitute a lousy deal.

Because those same UMDs aren’t rewriteable, your own music and photos can be stored only on a Memory Stick Duo card inserted in a slot on the PSP’s side. This cut-down version of Sony’s proprietary, expensive Memory Stick format can’t be used in a regular Memory Stick slot without an adapter, but Sony doesn’t include one. Nor does it include the USB cable you’ll otherwise need to connect a PSP to a PC. (At least the PSP’s standard-size USB jack accepted the cable from my handheld organizer.)

Once you’ve obtained an adapter or USB cable, copying music and photos requires creating a particular hierarchy of folders on a Memory Stick Duo, without which the PSP can’t find your files. If you, unlike most, have downloaded songs from the Sony Connect online store, you’ll need to use Sony’s SonicStage program to transfer those files.

If you get a PSP, do yourself a favor and stick to the games. If you also want to listen to music and view your pictures, just get an iPod Photo or another music-plus-photos player. What if you don’t want to carry around two expensive gadgets all the time? Then you’ve got a problem — and so does Sony, until it revisits the PSP’s multimedia software.