Fighting with mechs never looked so beautiful, at least from a bird’s-eye view. Carbon Games is launching the open beta test of its free-to-play AirMech game today as a downloadable title on Valve’s Steam digital distribution platform.

Carbon Games built the real-time strategy title with no outside funding and a team of six people. It looks beautiful and has more than 420,000 beta testers. You can play AirMech cooperatively or competitively online on the PC. The sci-fi game is akin to a tower defense game, with pretty graphics. But it runs on low-end hardware, including mobile phones.

Bellevue, Wash.-based Carbon Games was founded in July 2011 by James Green and Ken Klopp, who were among the makers of the Sony PlayStation Network game Fat Princess. Carbon built AirMech with a few hundred thousand dollars of its founders’ own money, said Green, and it is running across 23 servers scattered around the globe.

“Our plan is to crush all competition by offering ‘fair’ free-to-play that the big companies just can’t compete with because they have tens of millions to recoup,” Green said. “Our profits are going to be reinvested back into the game because we love it and want to build a trans-media empire out of it — not because we’re in it for the money. It’s because we love this game and want to prove that you don’t need a ton of venture capital to do it.”

Green said that Carbon has an Android version up and running at 30 frames per second on Tegra 3 tablets and also has a Google Chrome Native Client version. The company has an Ouya development kit and plans to launch AirMech for that platform. Its soundtrack comes out Tuesday, a work from electro-industrial performers Front Line Assembly.

Rivals include games such as League of Legends, StarCraft II, and Dota2. Green and Klopp met while working in Shanghai for Ubisoft. They both founded Titan Studios and then merged it with Epic Games China. After Epic Games China wasn’t interested in their pitch, they set off on their own.

Green added, “We are proving that the old publisher model is broken. Six people in a room can make a game played by people all over the world. I was tired of AirMech being rejected time and time again, and I knew the only way to get it made was to make it ourselves, fund it ourselves.”