The top-down dual stick shooter has been a staple of mobile gaming for years, but that doesn't mean it's all played out. JoyJoy from Radiangames has a neat look and customizable controls. Oh, and there are no in-app purchases, an increasingly rare attribute.
JoyJoy contains 24 waves of baddies, each with its own unique challenges. Your weapons are upgradeable, along with your ship. Though, "ship" might be a bit of an overstatement.