shield.nvidia.com | $300: Originally planned for a late June release, Nvidia's entry into the portable gaming space will now arrive in stores this week. The Shield, first introduced in January at the Consumer Electronics Show in Las Vegas, is the latest Android-powered handheld designed to give gamers the ability to kill some time with downloaded titles from Google Play or Nvidia's TegraZone stores. The mobile console also can stream PC games via Wi-Fi. But what Nvidia hopes will set its sleek clamshell-designed device apart from the smartphones people currently use to play games on the go is its powerful Tegra 4 mobile processor, a 5-inch touchscreen that displays video in 720p, with speakers and a built-in game controller that feels comfortable in the hands of Xbox 360 or PlayStation 3 owners. All of this comes in a lightweight package — even lighter than most tablets. At $300, the pricetag's a little steep, but Nvidia, known for products that appeal to hardcore gamers, is aiming its Shield at a crowd that's looking for a powerful mobile videogame console in their pocket.