Amazon Free App of the Day:

JoyJoy is the new fantastically satisfying twin-stick shooter from Radiangames, creators of Inferno+, Ballistic SE, Super Crossfire, and more.

* Blast your way through 24 unique waves and 6 intense challenges.

* Upgrade 6 varied weapons, along with your ships’ speed, armor, and special attack.

* Choose one of 5 difficulty levels, with 2 bonus difficulty levels (Lightning and Armored) providing new ways to play the game.

* Track your progress with achievements and leaderboards