It was supposed to be Christian gaming's Passion of the Christ moment. A turning point where religious games would go from mocked underdogs to mainstream contenders. Just as Mel Gibson stunned Hollywood in 2004 by turning his religious pet project into a box office smash, Left Behind: Eternal Forces was hyped as the game that would transform Christian gaming.
Everything seemed in place. A distribution deal with Wal-Mart, a publisher led by an ex-EA industry veteran and a decent wad of investor cash. And, crucially, the rights to the Left Behind books – a series of action-packed, post-apocalyptic Christian novels set after the Rapture that had sold in excess of 65 million copies.
Needless to say, the 2006 real-time strategy game never lived up to the hype. Savaged by critics, snubbed by shoppers and entangled in controversy over its content, Eternal Forces managed sales of just 100,000 copies. While good for a Christian game, it was a performance that publisher Left Behind Games described as "considerably short of our expectations".
After that failure, it wouldn't have been a surprise if Christian games faded away. If a well-funded, big-brand title with that much hype couldn't make it off the shop shelves what hope was there for the scrappy, underfunded and often dreadful output of most Christian developers?
But five years on from the false dawn of Eternal Forces, the Christian games scene is fighting on. In July the annual Christian Game Developers' Conference will celebrate its 10th year and the mood among Christian game makers is upbeat.
Chris Skaggs, the founder of Christian developer Soma Games, says one reason to be hopeful is that the barriers to game development have come crashing down: "When I was starting Soma Games in 2005, the only way to start was going into console games, but getting into consoles was so expensive – you needed a million dollars cash for Xbox to even look at you."
The spread of broadband, smartphone apps and free development tools has made developing cheaper and easier. As a result Soma joined the app game party and scored some success with G: Into the Rain, a sci-fi physics puzzler influenced by Spacewar! and the story of Noah's Ark.
Tim Emmerich, founder of the Christian Game Developers' Conference, says the rise of such tools has transformed the development landscape: "It's been a revolution for the whole industry and Christian teams have been able to take advantage of that."
At the same time, Christian studios are starting to move beyond their traditional offerings of tedious scripture quizzes and Biblical kids games.
"Christian games divide into two groups," says Emmerich. "The overt where it is obviously Christian and based on the Bible, and the covert games that look like regular games but where the underlying idea communicates some Christian aspect."
Skaggs sits in the allegorical camp: "We lean on what C. S. Lewis said when he wrote The Space Trilogy. He wanted the books to appeal to people who would never go to church and encourage them to think about eternal things. I feel our role is not to be Christians making games for Christians, but to put ourselves, including our Christianity, into mainstream work."
He says it's an approach that echoes the game industry's wider efforts to bring more depth into games. "At the last Game Developers' Conference, the conversations were almost universally about how gaming is maturing and how that requires us to bring more meaning into games," says Skaggs.
"It's really about storytelling. Look at Japanese RPGs – they are rich with mythology and spirituality. We accept it because in the game world we're looking for the epic story."
It's a belief echoed by Vertigo Games, the Dutch creators of the Adam's Venture titles. While the adventure game series owes as much to Indiana Jones as it does to Christianity, Bible stories are central to its narrative.
"It's more about what the stories are, rather than saying you should live your life according to us," says Tristan Lambert, the non-Christian co-founder of Vertigo.
"What to make of those stories it leaves to people to decide for themselves but it does try to raise your curiosity. I do believe whether you're Christian or not that, given our culture and history, everybody should know at least the basics."
But getting lumped in with other Christian games is a worry. Erik Schreuder, CEO of Iceberg Interactive – the publisher of Adam's Venture, says the poor reputation of Christian games is a concern: "Christian games might not have the best reputation outside of Christian channels as far as graphics and overall quality go."
Lambert admits the Christian element of Adam's Venture often works against it: "Over and over we have to explain to stores and distributors and whoever that this is something different. So yes there are Christian elements, but no we don't try to convert you.
"The best way to explain it is to let people play the game, but sometimes it's hard to convince them to even bother because of the negative reputation of Christian games."
Skaggs says Christian games have traditionally suffered from two big problems: a lack of funding and a tendency to force teaching into games at the expense of fun.
One way round the funding issue is teaming up with Christian organisations as was the case with YaHero. Bankrolled by the Canadian Bible Society, YaHero is a massively multiplayer game for eight- to 11-year-olds best described as a blend of Club Penguin, World of Warcraft and Sunday school.
"We wanted something to plant the seed of God's word into the heart of children and to find a balance between Biblical engagement and a fun environment," says Marta LoFranco, communications director at YaHero Inc.
But for Skaggs the ultimate goal is to get serious venture capitalists to support Christian developers so they can produce better quality titles. But that will probably need that The Passion of the Christ moment first.
"Someone needs to make a mainstream title that has reasonable success so these people know there is a market," he says. "The Passion of the Christ got investors' attention and investors don't have to be motivated by faith, they can be motivated by the numbers."
Left Behind: Eternal Forces and Adam's Venture 2 are both out now on PC.