The Zune HD may not have set the MP3 player market on fire, exactly, but it's a quality piece of hardware with a slick and attractive user interface. It's also a platform that developers can write games for. Unfortunately, third party games on the Zune are restricted in what they can do; they must be developed using Microsoft's .NET-based XNA Framework. This wouldn't normally be a problem, as XNA usually offers high-performance Direct3D graphics. However, on the Zune HD, XNA supports only simple 2D graphics, and no hardware accelerated 3D. The result is lackluster graphical performance, even though the NVIDIA Tegra powering the Zune HD is highly capable. The restricted environment also prevented third-party applications from accessing the Internet through the device's WiFi connection.

Enter the OpenZDK. Through exploiting a flaw in the Zune's firmware, it's possible to run native applications on the Zune. This exposes the full power of the Zune's hardware to developers: most importantly, programs can use the widespread OpenGL ES 2.0 API (the same 3D API that the iPhone supports) to exploit all the capabilities of the Tegra chip. This in turn allows third-party applications to achieve the same quality as Microsoft's own Zune games like Project Gotham Racing: Ferrari Edition.

As those Microsoft-published games demonstrated, the Zune HD hardware is more than capable of providing a first-rate gaming experience. PGR, in particular, is both fun and extremely good-looking. Until now, however, the restrictions on third-party developers have left that power largely untapped.

It should be fairly easy for developers to get up to speed on native development with the ZDK. The Zune HD operating system is based on Windows CE 6 (as will be the forthcoming Windows Phone 7 platform), so development and deployment is quite easy: this is a widely supported and well understood OS. OpenGL likewise is something familiar to a lot of game developers.

However, the fun may not last long. Just as Apple has fixed exploits allowing jailbreaks on the iPhone, Microsoft might well choose to fix the exploit (or exploits) that are being used to enable native Zune development. In many ways, this would be a pity. The Zune HD clearly has a lot of potential: it's too bad that it requires hacks to live up to it.