YoYo Games is the creator of the very fast and easy to use cross-platform games development technology GameMaker: Studio. GameMaker: Studio has been developed with usability and efficiency at its core, allowing developers to create games in a single code base and then export and run them natively on multiple formats, including (but not limited to) the Windows Store. GameMaker: Studio combines a powerful, yet simple, drag-and-drop integrated development environment with a built-in games-oriented scripting language to considerably increases games development productivity. Whether you are an entry-level novice or seasoned game development professional, you will find value in this development environment.
Check out the videos below as they will help you familiarize yourself with YoYo Games and their community, as well as will provide task-based "how to" guidance specific to Windows 8 app development with the GameMaker: Studio framework.