One of the delights of a well-designed role-playing game is the feeling that you're exploring uncharted territory.

The stories may be intriguing, the battles may be pulse-pounding, but the real thrill comes when you discover a new city, an abandoned ruin or even an unsettled planet.

That's why RPGs can take 40, 60 or even 100 hours to play: You never know if that rock you just stumbled over may be hiding the gateway to another dimension.

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A great RPG is like a Tolstoy novel, with a compelling story bolstered by a variety of subplots and digressions.

Even when the game is over, there's a temptation to go back and wander down some of those unexplored byways.

Fortunately, RPG designers know we're always hungry for more — and always eager to revisit the worlds they've spent so many years building.

— "The Elder Scrolls IV: Shivering Isles" (Bethesda Softworks, for the Xbox 360, $30): This expansion pack for last year's brilliant "Oblivion" delivers about 30 hours of fresh action — more than most full-priced games. You have to download it from Microsoft's Xbox Live Arcade, so if you're an "Elder Scrolls" fan, it's time to get hooked up.

A portal takes you from the relatively benign land of Cyrodiil to the realm of Sheogorath, an insane prince who's prone to saying things like "Come visit again or I'll pluck out your eyes!"

Sheogorath's kingdom is divided into two sides: the colorful Mania, home to high-strung eccentrics, and the muddy Dementia, whose citizens are more fearful.

The prince needs your help stopping an approaching menace, and sends you on a series of quests.

There's a nice variety to the missions, ranging from stealthy detective work to bloodthirsty monster hunting, and the plot features a number of clever twists.

You can also take on jobs for the locals or just do some freelance treasure-hunting. It's a satisfying side trip; alas, it probably represents Bethesda's farewell to this engrossing world.

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

— "Final Fantasy Fables: Chocobo Tales" (Square Enix, for the Nintendo DS, $29.99): One constant in the long-running "Final Fantasy" series is the chocobo, a giant, chicken-like thing that's used more for transportation than for food.

The chocobo takes center stage here in a lighthearted adventure that combines role-playing, card battling and an assortment of arcade minigames.

After the chocobo's friends are imprisoned in an evil book, he has to rescue them by hopping into various stories and rewriting the endings.

Typically, that involves beating a short action challenge, which rewards you with a friend to return home, a new area to explore or a new card to play with.

Those cards become the basis for an engaging card-battle game, similar to but simpler than "Magic: The Gathering" or "Yu-Gi-Oh!"

It's a good introduction to the genre for younger players, but more experienced gamers will find it challenging at times.

"Fables" may be too cute for some "Final Fantasy" vets, but this is one tough bird.

Three stars.

— "Shining Force EXA" (Sega, for the PlayStation 2, $49.99): I played the original "Shining Force" back in 1992, but I'll admit that I've been negligent in following all its permutations since then. (Wikipedia lists 20 "Shining" games.)

You don't need to be familiar with the series to pick up "EXA," although it will try your patience in other ways.

Let's start with the generic plot: A warrior and a sorceress try to bring peace to a world shattered by a long-running war. It's a mission that, typically enough, requires the team to run around killing monsters all over the planet.

There's a lot of fighting, and it quickly gets dull; most of the time you just need to pound on one button over and over.

The most innovative, entertaining parts of "EXA" involve the reconstruction of the Geo Fortress, a huge, moving castle in which you can beef up your weapons or build up your skills. Unfortunately, you have to go through a lot of boring battles to find the resources you need.

Two stars.