Microsoft (News – Alert) has been pushing for more app milestones in its mobile app markets — the Windows Store for Windows RT tablets, and the Windows Phone Store for, you guessed it, Windows Phone (News – Alert) devices — and although the latest Windows Store release, that of “SteamPower1830” isn’t as monumental as Instagram for Windows Phone, it’s still a major release for the platform. That said, the release of this premium HTML5 game is less of an occasion for Windows RT users and more of an occasion for HTML5 game development itself.

Developed by Hexagon Game Labs, SteamPower1830 is a free-to-play online game that leverages both the proprietary, HTML5-based Ubique Game Engine, as well as Microsoft’s Windows Azure servers. The result is a unique strategy game that provides a next-generation, cross-device and cross-platform gaming experience. In other words, game sessions can be shifted at any time between all supported platforms, including the Microsoft Surface, PCs and Windows Phones.

Cross-platform gaming was cited as one of the primary goals of Hexagon Game Labs back in October when SteamPower1830 hit the closed beta stage and it seems partnering with Microsoft was the best way to make this a reality.

“Microsoft’s open, multi-platform philosophy is a perfect match for our cloud-based, platform-independent HTML5 approach,” said Jan-Hendrik Ohl, CEO and founder of Hexagon Game Labs, in a statement. “Windows Azure provides us with a dynamic back end that enables cost-optimized scaling without us having to worry about performance bottlenecks. Programming the SteamPower1830 app and submitting it to the Windows store proved to be very developer-friendly.”

SteamPower1830 allows players to continuously expand a railway empire on any end device by saving game statuses in the cloud. This means the game will play the same, and pick up from the player’s last saved state, whether it’s launched via the new app or from a Web browser.