YOU DON’T HAVE TO be a Doritos-munching, Red Bull–chugging teenager to cheer the news: The Fire is one wicked fun gaming machine. Whether you’re into angry avians or you just like your morning Sudoku, the Fire is ready to frolic. The device’s easily graspable size is a big factor here. You can pull it out of a shoulder sling or pocketbook any time the mood strikes. And thanks to the hard work of developers worldwide, the range of titles in Amazon’s Appstore for Android is already decent, even in the Fire’s early days. Dozens and dozens of choices await (yes, including Angry Birds) in categories like arcade, educational, racing, and sports. In fact, selection overload is precisely the problem that stumps some fans eager to get their game on....