Hexage has been a fixture in Android gaming since the very beginning with titles like Radiant and Buka. The latest title out of Hexage is a strategic battle fortress builder called REDCON. It's got big guns, solid graphics, and in-app purchases designed by a sane human being. What more do you want?
REDCON follows the story of you, a strike commander in service of the Empire State. The rebels are surprisingly well-equipped, but you've got a customizable battle fortress. Each level consists of your guns firing repeatedly as you designate targets on the enemy fortress. If you've played Canon Brawl on PC, this looks similar. As you destroy enemy installations, you gain experience that unlocks more fortress designs and weapons.
The game looks nice with that usual Hexage style and has (from my brief testing) very enjoyable gameplay. You could say that about a lot of other free games only to be put off by in-app purchases, so what about REDCON? The system is similar to the developer's last big release Reaper. You can play the first 18 levels free. After that, it's $2.99 for the full game. You can also pay either $4.99 or $5.99 if you want bonus content like extra layouts or weapons. There are no ongoing IAPs.