Picked up Hex Defense from Amazon Appstore Giveaway of the day.
I've tried Hex Defense before. It's basically a geometric version of Tower Defense, with the enemies emerging from one hex. The idea is to stop X of them from going through the exit hex. You got four types of turrets: gun, laser, missile, and field. Each can be upgraded multiple times.
The "level" is limited to about 20-30 waves, so there is an end, not infinite. There are like 20 different "levels" or fields to play on, and each have different type of challenges.
Definitely worth trying, if you like this genre.
Rating: Try it