The best Tower Defense Game

This is the game that got me hooked on Tower Defense style games. I keep looking for another game like this but nothing comes close. Controls are responsive, work great with touchscreen, difficulty is perfectly balanced, lots of levels to keep you hooked.
Bonus points to criterion for realizing that many want to be able to mute all game sounds and listen to our own music or podcast while we play. You can do that with this game.

Overall great game.

Developers are also responsive: I emailed them that the game was broken (due to Open Feint glitch) in a week or 2 a new version was up and running.

Only gripe is that Criterion doesnt make a new version already. We need more GeoDefense!

biznash about geoDefense, v1.7