6 combat units over four "tech" tiers. It's only got one mode at the moment and the actual base building is a little limited. But it is incredibly fun and challenging, and at the price I got it for (22.50) it has so far sucked up at least 15 hours of my life, so currently worth every penny.
That said, there's some UI jankiness that isn't game-ending but is also mildly annoying. The buttons to build stuff doesn't always depress when clicked, and it almost seems like there is a specific location on the UI you need to click inside each button to get it to work some of the time.
So far I've only seen 6 enemy types total, with the slow moving zombies, fast moving zombies, citizen zombies, fatties, spitters, and harpies. Little limited but it is enough, imo, when you have thousands of the fuckers running at you at once.
Actual campaign/story stuff coming early next year, and hopefully a little more fleshed out technology stuff with more unit and mob variety. Otherwise, it's a very fun little game.
