Many indie game developers are keen to tell stories with meaningful messages, but making sure that message is understood can be an enormous challenge.

That was the takeaway from today's Independent Games Summit session at GDC on Tomorrow Games' quirky fireplace simulator Little Inferno. Kyle Gray, one of the game's designers, walked attendees through "the many mistakes" the team made during development.

"If you have a message in your game, the chances are people aren't going to get it," he said. "A lot of people thought Little Inferno was about global warming or a critical commentary on freemium games, but it wasn't."

In Little Inferno, which was an indie launch title for Wii U and has since been ported to Windows PC, Mac, Linux, Android and iOS, players order goods from an Amazon-like catalog and then toss them in a fireplace. Items and combinations of items give up different effects in the fire. But the story unfolds into a larger, darker narrative.

"What we were trying to talk about was the team's own neurosis, that we were all hitting 30 years of age and feeling old," he explained. "We were concerned with time; making the most of it and not wasting it, like getting out of a job you hate or a bad relationship. People in Little Inferno are just doing the same thing and they don't realize there is this whole world out there."

He said it was "fine" that the message didn't seem obvious to many players, and pointed to various online commentary debates about the issue. One of the main problems, he said, was that a significant element of the story was backloaded to the end of the game, which switches, in its final sequences, from the fireplace-view puzzle to a more narrative-based adventure.

"It's really risky to put all your cool content at the end of the game," he said, adding that the team "over-thought" the project, spending two and half years on a development that was originally scoped to last six months.

Ultimately, the promise of launching with the Wii U focused the team on tightening the game, and getting rid of ideas that were considered superfluous, including a section featuring a time-traveling subway. To date, he said, Little Inferno has sold more than a million copies.