For this challenge it will require to load up the free to play StarCraftII from Blizzard! Once you have logged in select campaign and Click on Episode I. From there you will select challenges.

Winners will be selected by achieving the highest level medal on For the Swarm challenge. Ties broken by the fewest units lost.

Click here for an example screenshot.

IF you are new to StarcraftII you can even do this challenge! The challenges actually give you a chance to learn about each character and of what counters what at your own pace.