[Android] Free: Data Defense (Was $6.49) @ Google Play Store

No, not a security app but a fun, free game.

Data Defense is a minimalist tower defense indie game set in cyberspace. Protect servers from being infected by a slew of oncoming glitches, bugs and viruses. Use each server's particular layout to your advantage, installing defense programs in strategic locations to defend the server in the fastest time possible.

GAME FEATURES:

★ No Ads or internet connection required!
★ Create and change the path by installing, selling and upgrading your towers
★ Over 50 different maps and challenges
★ Customize your strategy with 30 different towers
★ Enjoy both Campaign and Survival modes
★ Loads of unique enemies that will put your defense skills to the test!
★ Amazing ambient music with over 15 tracks
★ Hours of gameplay!
★ Beautiful vector art
★ Amazing physics driven particles!

via imnobody at OzBargain