After all, today’s games usually model themselves not on television but on movies. They take forever to develop, come out infrequently and require a big commitment of time from the audience. Game developers figure that if they ask us to wait years for a game, and then demand 40 or 50 hours to play it, it’ll be an emotionally intense experience.

But a new generation of “episodic” games is challenging that wisdom — developers are crafting titles that function more like a TV series. Valve recently released the first “episode” of a Half-Life trilogy that will span the next year. Another game company, Ritual Entertainment, is crafting a series from its SiN franchise. Like TV shows, each installment will be a bite-sized chunk — a mere four or five hours of play — that collectively builds into a big story arc. If they’re successful, the future of gaming will look less like Casablanca and more like The X-Files.

About time, I say. Breaking a “big” game into smaller pieces fits perfectly with the rise of casual gamers — adults with busy lives (read: me!) who want to play games in short blasts, instead of being forced to pencil off an entire weekend. Sure, I loved the cinematic scope of the enormous Half-Life 2, but what a haul: It took so long to play I wound up blowing the deadlines on two projects at work.

Playing Episode One, in contrast, was a compressed quantum of fun. The game opens up where Half-Life 2 leaves off, with Gordon Freeman and his hottie partner, Alyx Vance, surviving a huge explosion. Freeman plunges back into the wreckage to try and stabilize the situation, and pretty soon you’re in the thick of the story — navigating a gorgeously post-apocalyptic world, uncovering the alien conspiracy, and using Half-Life 2’s awesome gravity gun to toss around enemies like rag dolls.

And it’s fast. I plowed through the game in a mere two sittings, hit the cliffhanger (no spoilers; I can’t risk fanboy assassination) and came away itching for the next episode. Hard-core gamers might complain that’s too short. Not me. I got that satisfying sense of completion that I often miss in a normal “big” game, when I realize I’ll never have time to play the whole 50 hours, and reluctantly abandon it halfway through.

But brevity isn’t the only benefit here. There are also artistic advantages. Episodic play lets gamemakers tell stories in new ways — because serialized narrative has a literary style all its own.

The whole idea of episodic stories was born in the 19th century when the printing press made cheap magazines possible. Writers like Charles Dickens hit upon the idea of delivering a big story in weekly chunks, each with a cliffhanger to keep the audience in anticipation. (The cliffhanger is essentially a technological invention — a direct result of the movable-type press.)

Dickens soon discovered that he could now do innovative things with his story. His characters’ personalities could be developed not through single, central scenes, but through a dozen glimpses over a long stretch of time. Serial narrative also changed the way audiences relate to characters. When we focus on movie characters for two solid hours, they become epic heroes; when we encounter TV characters every week for years on end, they become old friends. There’s an intimacy to episodic stories, and it’s all the more intensified in a game because you literally go through hell with these folks. After Half-Life 2 and Episode One, I was pretty much in love with Alyx, one of the spunkiest and best-acted virtual characters I’ve ever seen.

Serial narrative also lets writers create increasingly labyrinthine plots. Audience members can tolerate only so many twists and turns in a single, monolithic movie before they get confused. But in an episodic narrative, a writer can weave oodles of subplots — because we’ve got months and years to puzzle them over. The tangled plots of Lost simply wouldn’t be possible anywhere other than episodic TV. Now imagine how dense and twisty Half-Life or SiN could become if the game companies stretched them out to five, 10 or 50 episodes.

There’s a technological upside too. Rolling out episodes every few months means game designers can tweak the graphics and physics as they go — rather than waiting years to bundle their innovations into a single title. Valve took an agonizing six years to develop Half-Life 2 because the company kept pushing the graphics further and further. But the new episodes grow incrementally: Episode One has better lighting than Half-Life 2, and Alyx’s face is already three times more complex than before.

Gameplay can evolve, too. Ritual’s developers say they’ll use fan feedback to help tweak each new episode — taking out lame weapons, adjusting the plot line. You can’t have that level of flexibility when you’re betting the farm on one monolithic game every four years. “We can take more risk than ever before,” Valve President Gabe Newell told me.

How far could the episodic experiment go? Even Newell doesn’t know. Maybe they’ll discover that fans want games to be even shorter and more frequent. Imagine getting two new hours of Half-Life every month. Or one hour every week!

Like the man says: Don’t touch that dial.