The free-to-play option includes the complete Wings of Liberty single-player story campaign (which, incidentally, earned a 9.5 rating from GameSpotwhen it debuted in 2010).
You also get access to all multiplayer units in the Unranked Multiplayer and Custom game modes. You can access the Ranked Multiplayer ladder by completing 10 “First Wins of the Day” in Unranked Multiplayer or Versus AI modes.
Meanwhile, you can play co-op mode, with free co-op commanders up to level 5 and that includes Terran commander combo Mira Han and Matt Horner, who are debuting today as part of the free-to-play launch.Finally, if you already own Wings of Liberty, you can get a free digital copy of the expansion pack Heart of the Swarm — though have only until Dec. 8 to obtain that.Starcraft II is available for both Windows and Mac, but before you can get it, you’ll need a Blizzard Battle.net account. If you already have one, great.If not, you can sign up for one after downloading the installer, which you do by clicking Play Free Now on the Starcraft II home page. (Curiously, when I did that a little earlier today, I was directed to a Battle.net page where I had to create an account prior to downloading the installer. But now it seems that requirement has been lifted, as clicking that button immediately downloads the software.)