Well, not just Blue Shift (duh), you also get Opposing Force, and a High Definitions pack. Also, unlike OpForce by itself, Blue Shift does not require Half-Life to play. If you don´t already have OpForce, this is a steal, and if you do, you can get a $10 rebate with it. The High Definitions pack basically adds detail to all the people and enemies, and then spruces up the look of your weapons.