If there's one true thing in this crazy gaming world, it's that there's no formula for success. But there are ways developers can help their odds. Dublin developer SixMinute, for instance, has made a game that's instantly familiar yet innovative. Initially, Pick a Pet looks like Jelly Splash or Candy Crush: You are given limited goes to swipe matching objects (big-eyed gummy sweets this time) and make them disappear. Then the tactics emerge: Every dozen levels you're given a bonus "pet", a cute mythical animal that helps you in a unique way – zapping extra gummies, for instance, or crossing barriers to vanish specific ones. The trick is to make the most of your limited turns, and to use the right animal at the right time. Pick a Pet – a freemium game – has an undeniable one-more-go quality, as the varieties of pets encourage trial and error. sixminute.com