Where on earth do I begin with this one. Right. Okay, what is it? It's not a traditional strategy game in the usual senses of the word. It's not an RTS in so much as that the forces are hideously asymetric, and it's not Turn Based either. I would call this a "Swarm control" game, where the concept is that you have a small number of deployable troops, as well as static defences, and from this you have to construct a working strategy that funnels a much larger force into killzones and crossfires.
Combat works on scales that you don't generally get to think about in such games, your 4-7 little poxy marines will end up riddling thousands, yes, thousands of enemy aliens with holes over the space of one mission, and quickly you stop viewing the enemy as a mass of individuals, but as mentioned - a swarm, one to be controlled, funnelled, and pushed back.
When you finally "click" with the concept, and you start figuring out how to approach the swarms and manage them, the game suddenly starts falling into place, systems and mechanics which were until then entirely unmanagable become second nature and intuitive, and you quickly fall into the habit of securing outposts, setting up turret crossfires, assessing where you can do the most damage, how to maximise your soldiers efficiency. You stop thinking in individual terms and if anything, approach the mission almost in a "grand strategy" way of things. That's the beauty of infested planet.
Graphics and sound are decent, it's an indie effort, and the graphics achieve what they set out to do (you won't get confused and lose track of what's going on, be thankful), ditto for the sound, the plot too, again, servicable, but the gameplay clicks, it takes a while to get over the learning curve, because the game is so radically different from what most people will be used to, but the investment eventually does pay off. The experience is very much unlike anything else around, and is definitely worth checking out if you fancy a change of pace from normal RTS experiences.