I'll link this page so that I don't have to go through and basically retype all of it: http://www.servogame.com/game/gameplay
To expand on what is there, you currently start each game with a single servo and a smattering of drones. Using those units, you can spread out to capture bloom nodes on the map that provide you resources. Using those resources you can build turrets, drones, or research tech that can either unlock more units and the ability to call in more of your servos, or upgrade the ones you have. Currently, you must pay to rebuild destroyed drones from your factories, though dead servos instead go on a cooldown before you can call them back into the fight for free. You win in PvP by destroying the enemy Dropship, and win Co-op by surviving waves of enemies or destroying meteors that spawn them continuously. Between matches you spend the credits you earned after each match on purchasing new gear, mixing up your loadouts, and optimizing your servos for your strategy.
I find it to be quite a lot of fun. I enjoy the eternal quest for better loot and new options/strategies and the servos are always fun to customize and mess with. Plus it's a game about 100 ft+ mechs destroying each other and everything around them, so what's not to love?
