I am a big fan of Tower Defense games.
Last year, I wrote a comprehensive review of the best tower defense games on iOS.
Lately, I have been playing Radiant Defense.
The storyline is that portals are opening outside the planets in your system. Creatures are appearing in waves of ever increasing difficulty. You play both military leader and chief scientist as you build towers and research new ones. There is well placed, snarky banter between “you” and the alien leader at wave breaks.
Radiant TD has a build your path approach to gameplay. You are given a set of modules for at the start of each level and more for each wave completed.
There is a great selection of towers. More towers become available after you build the research tower. The only paid upgrades are to give you access to the most advanced towers in the game.
The alien enemies number in the dozens. The game also brings enemies at different rates of speed and combinations. That variety keeps the games constantly interesting.
There are points in the game when I wish I could have a little more control over the towers by either setting the direction or being able to target a specific enemy. Lacking those controls you learn how to build routes that minimize the targeting movement that towers make.
My main hint is make sure you use all types of towers. As the difficulty of the levels increases, you’ll need them.