And, that's one of our favorite things about Hexage. Unlike most developers who implement the free-to-play system, you can still have fun with a Hexage game even if you don't pay. Most free-to-play games essentially force you to pay by ramping up the difficulty or making you grind, and then overcharging you. But, Hexage keeps gameplay varied enough to make the game fun even if you don't pay, and if you want to support the dev, you can get a pretty sizable power-up for just $3.
In Radiant Defense, you'll have to defend yourself from 300 waves of enemies spread out over 10 levels. You'll have 9 weapons and 3 super-weapons with which to defend yourself, and of course there's the relatively standard online leaderboard and such. And, if you are the type of person to turn down the sound in a game, you may want to at least give this one a try, because the soundtrack is pretty sweet.
Radiant Defense is available for free in the Google Play Store.