#6
Element TD 2 grew out of a Warcraft 3 custom map, and you can still feel that heritage in how it handles economy. You earn interest on unspent gold, which means deciding when to build and when to hold becomes its own mini-game running parallel to the wave defense. Then there are element combinations: building two different single-element towers near each other can unlock a combined tower with better properties than either alone. It is the kind of system that sounds complicated and clicks fast once you grasp it. Not the flashiest entry on this list. If clean strategic puzzle-solving over presentation is what you want, it delivers.