its pretty unique and can be fun at times, but at other times, it just doesnt add up.
the tower deployment and upgrading process looks good, and the visuals are somewhat nice ;) but you require a steam account to play the game, which can be annoying.
but dont worry! now for the details
ok, your defending an invaded planet, and you deploy turrents on little panels, they will shoot the enemy after deploying in a cool way
they are trying to get the power cores at the end of the map, you have a limited number of them. if all of them are taken, you have not lost though! an enemy will turn back the way they came (on most levels) after they take a core, just kill them before they get out, and the cores will be dropped, and slowly float back to your core supply.
win a level simply by defeating all waves of enemies