Blastron was already for a while available in the App Store, and is now also available in the Google Play store. Graphic quality aren't great, but it looks more than good enough for a free game. Those images are also quite child friendly. The game has an average rating of 4 stars. The single player game is primarily intended for the collection of such new weapons and upgrades.
iPhone/iPad: download Blastron (free, iOS 5+, 4 stars)
Android: download Blastron (free, iOS 5+, 3.6 stars)
Hero Forge is actually a clone of Puzzle Quest, the famous puzzle game with RPG elements. The game is available for free on Android devices. By solving the 'sliding puzzles block' a bit of mahjong like, you can attack your opponents. With all the experience points you have earned, you can buy new items, weapons, armor and upgrades your skills. The game as an average rating of 4.6 stars.
Android: download Hero Forge (free, Android 2.2+, 4.6 stars)
Drop Chord is a music game from the creators of Classic Psychonauts and Brütal Legend, the metal game with Jack Black in the lead. The latest project of this interesting game developer is available for iPhone, iPad and Android devices. In this game you control a beam of light that you have to keep in line with the electronic music. You do this with your fingers.
iPhone/iPad: download DropChord ($1.99, iOS 5+)
Android: download DropChord ($1.99, Android 2.3.3)