Long after Zynga, Playdom and other top social game developers have given up on making new Mafia Wars-style RPGs for Facebook, a small studio near Sacramento called 5th Planet Games is still releasing new titles in the genre.

The latest is Legacy of a Thousand Suns, a space opera reminiscent of Star Wars. While 5th Planet hasn’t iterated much on the mechanics of its RPGs, it has made significant advances with the story and style of the game over Dawn of the Dragons, the company’s first title.

Thousand Suns doesn’t actually look a lot like Mafia Wars — more on that in a moment — but the setup and mechanics are quite similar. Your character is only seen in a profile screen, while missions are accessible through a tab. As in all similar games, missions don’t require any skill, just enough energy to click through and get to the next mission. There’s also crafting, alliances, boss battles and player vs player battles.

The centerpiece of Thousand Suns, though, has nothing to do with mechanics. 5th Planet has used its game to slip an almost novel-length text story to users, with each mission and boss battle illustrated by beautiful, sometimes full-screen art created by 5th Planet’s development partner, Concept Art House.

Thousand Suns’ story is interlaced throughout the game. Your first mission is a daring escape from jail, assisted by a Leia-like Princess. The game’s tutorial guides you through the first part of the story, and then leaves you to find the rest alone.

It’s not hard to find. Each new area comes with a Zone Intro, a button near the top of the screen that opens the story for that area. Unlike Dawn of Dragons, which required users to seek out the story for missions, the mission start button automatically pops up the continuation of the story. And bosses, which show up in one out of every five missions, have both an intro and an encounter story, which combined usually run several pages long.

To 5th Planet’s credit, the company has used a professional writer for the game — the plot, which follows the conflict between a human and alien empire, has an engaging arc for as far as we made it through the game. And even beyond the many mission-related text boxes the game’s elements stay faithful to 5th Planet’s lore, from the items to ships and non-player characters.

In one sense, 5th Planet’s doubling down on narrative gives a sense of where Facebook RPGs could go. There’s a substantial niche audience who will be interested in playing through fairly standardized games for the storyline and feeling, much as has happened with Japanese RPGs. 5th Planet has also inspired some loyalty among this group by emphasizing player clans and interacting with users in forums.

But Dawn of the Dragons, despite the promising retention and monetization metrics that 5th Planet showed us in July, never became a large game, maxing out at around 300,000 monthly active users. Thousand Suns, with its new story and somewhat slicker interface, may attract more, but is unlikely to become a breakaway hit.

After playing Thousand Suns for a while, it’s hard not to feel like there’s promise of a significant evolution in the old Facebook RPG mechanics.

Funzio recently showed a more action-based possibility with Crime City, which to many developers feels like a graphical skin of Mafia Wars; 5th Planet, for its part, might benefit from something more like a graphic novel. With the art and text combo in Thousand Suns, it’s already half way there.