Don’t use the word “episode.”

Don’t use the words “expansion pack.”

Brian Allgeier, lead designer of the biggest short game of 2008, “Ratchet & Clank: Quest for Booty,” publicly uses the term “mini-adventure” to describe what he and about 20 other people at Insomniac Games made during the last 10 months.

Allgeier’s team has created the most polished, graphically complex and data-heavy (over 2GB to download!) game this side of the “Half Life 2” episodes. It has been released in the richest season of downloadable games in home video game history. It’s a a hypothesis: a guess about how much content developed with disc-game production quality standards should be delivered to a gamer for $15. And it’s a case study: proof of just what kind of effects a three-hour duration must have on the formula established in longer games of the same franchise.

And to think, it could have just been a space combat game, which is what Allgeier’s team had proposed:

Last August, Sony officials asked members of Insomniac to determine a way for the “Ratchet and Clank” game, in Allgeier’s words, to “touch the network.” Sony wanted to make the PlayStation 3’s online service, PlayStation Network, feel indispensable to fans of the “Ratchet” franchise.

“It was one fourth the game and one fourth the team.”

Insomniac developers proposed three ideas for downloadable content: 1) a “Ratchet” expansion pack, 2) a space combat game, or 3) a standalone level. Sony polled gamers and the favored choice was the third option. And so in October, just as the full-sized PS3 game “Ratchet & Clank Future: Tools of Destruction” was set to ship, 20 Insomniac developers started working on a projected three-hour download-only “level,” the mini-adventure that would become “Quest for Booty.” Comparing the endeavor to the scale of the PS2 “Ratchet” games, Allgeier said, “it was one fourth the game and one fourth the team.”

The mini-adventure would be pirate themed and needed to feel epic over the course of just a few hours — a short duration for the kind of video games that typically convey that epic feel. For reference, Allgeier bought “Pirates of the Caribbean 2.” He spent $15, decided “it wasn’t the greatest movie,” but enjoyed the experience. He wagered his team could convey at least that kind of reaction for “Quest for Booty.”

Insominac could borrow storytelling tricks and a Hollywood movie’s broadstroke presentation of character from a Summer blockbuster. What they couldn’t quite do was combine it with standard “Ratchet” gameplay material. The formula for the full-sized “Ratchet” games — the presentation to players of progressively more powerful, upgradeable weaponry — wouldn’t work. “We didn’t have time to set up all the weapons,” Allgeier said. Three hours wasn’t enough time to arm the player with a big arsenal. So the developers changed the formula for their short game, stripping “Ratchet” of his guns and power-gauntlets and grenades for much of the duration of “Quest for Booty” and focusing instead on platform-jumping. That type of gameplay could be presented briskly and develop quickly.

The creation of “Quest for Booty” wasn’t that much easier than creating a big “Ratchet” game. As a cautionary metaphor for why this was the case, one of Allgeier’s artists likened the “Quest for Booty” development process to a short day at the beach. It’s not the swimming and sun part that’s the caution. It’s the having to bring the same folding chairs, umbrella and all sorts of other stuff, whether you are planning to spend one hour at the beach or six. In other words, making a short venture requires many of the same tools as making the big one. Certain phases of development take just as long. The alpha, beta and gold periods of development for “Booty” involved just as much time, Allgeier. The same graphics engine needed to be worked on (if not built). That engine, brought over from “Tools of Destruction,” was tweaked to add some extra dynamic lights. The conversation system was improved.

“We thought a 3 hour game that is around 2 or 3 gigs would be a reasonable size.”

“Quest For Booty” needed to be grand and tiny at the same time. Together, the production values, the desire to create something that could feel Hollywood-epic and the $15 price of the game compelled Insomniac and Sony to create as large a small game as possible – but not too large, of course. Would they wind up asking too much of gamers and those gamers’ broadband connections? “We were very conscious of the download size of the game at the beginning of production,” Allgeir said. “Considering that HD movies are around 4-5 gigs and short game demos are between 1 and 2 gigs, we thought a 3 hour game that is around 2 or 3 gigs would be a reasonable size.” (The game is being released on a Blu-Ray disc in Europe but is download-only for the U.S.).

July and August 2008 have become a showcase of the evolution of downloadable games on consoles, with both PSN and the Xbox 360’s Xbox Live Arcade showcasing nearly weekly releases of original, acclaimed games such as “Braid,” “Geometry Wars: Retro Evolved 2” and “PixelJunk Eden.” Allgeier said he saw a season of games like this coming. “I think about a year ago there was so much buzz in the development community about episodic and short-form game development that it’s not a surprise,” he said. Nevertheless, his “Ratchet” resume didn’t exactly seem like something he’d be part of. “It feels like we’re part of a pioneering movement,” he said. “That’s an exciting feeling to go into uncharted waters and try new types of games.”

“It feels like we’re part of a pioneering movement.”

“Quest For Booty” ends with a teaser that promises Ratchet’s adventure will continue in the fall of 2009. Allgeier wouldn’t comment on that future, indicating neither whether the next game will be a full adventure or another mini. He did say lessons have been learned from working on the smaller game. He liked adding more platform challenges to the series and said that is “something we’d certainly apply to future adventures, big or small.”

But will the next “Ratchet” be big? Or will it be small? There’s no telling. “Quest for Booty” shows, at least, that developers can now, sort of, have it both ways.