What is StarCraft II?

http://us.battle.net/sc2/en/game/guide/whats-sc2

StarCraft II: Wings of Liberty is the long-awaited sequel to the original StarCraft, Blizzard Entertainment’s critically acclaimed sci-fi real-time strategy game. StarCraft II: Wings of Liberty is both a challenging single-player game and a fast-paced multiplayer game, and it also taps into Battle.net — Blizzard Entertainment’s fully-featured online gaming service. So, what exactly is StarCraft II? Read on and find out.