In the early days of StarCraft, players feared the clichéd Zerg rush—some gamers would simply spam as many cheap units in the early game as possible and overrun the opposition. StarCraft 2 saves us from this terrible fate, however, with one simple addition: rocks.

Placed in choke points, or at the entrance to your base on maps marked "Novice," the destructible rocks have 2,000 hit points, meaning weak units will be stuck behind them for a quite a while before being able to fight their way through. More powerful units will run right over them, but by that time both sides have had more than enough time to climb the tech tree and build some defenses.

You select whether or not you want these rocks in your game by choosing between the standard and novice version of the maps. When enabled, they act like rocky blankets, keeping you safe and warm while you build up a force and get some serious turtling going on if you're Terran. These are an easy way to stop rushes, but if you don't want to use them, you don't have to. It's the best of both worlds!

Look for more details and gameplay elements from the StarCraft 2 beta in the coming days and weeks.