You're the king of Orcs, zombies and demons, and you're keeping a huge treasure in a cave. The villagers have got to know this and now they're coming up towards it in large numbers. So you're going to protect your precious stones from being stolen! Your enemies come in through the entrance and go towards the cave. There they take a gem, and walk back to the entrance. Build towers in strategic places to stop the thieves. There are three types of towers: shelters, that you can only build on the grass, crypts, that you can only dig in the snow, and temples, that you can only place on rocks. You can't build anything in the woods. For each tower you need gold: keep your stocks up! Each killed enemy earns you gold. Towers fire automatically at enemies that come close. The more often they fire, the more experience points you earn for this, allowing you to upgrade the towers when you see an 'up' icon above.