File:Quake1.gif File:Globe.png Not to be confused with Quake II. File:Q2Addon.jpg Q2 or Q2 for Quake is a commercial add-on for Quake developed by Underworld Software. It was published by Micro Star and CrystalVision Brand Software. This add-on was released on November 11, 1996. It is possible to confuse this add-on with the similarly named Quake II, especially since the name Q2 is short for Quake 2.