CounterWolf is a mod for registered Wolfenstein, made by Ryan King. It was released on May 19, 2003 and saw many fixes and additions until the final version was released on August 2, 2003.
A version also exists under the name CounterWolf v1.641, and this is often confused for an earlier mod titled Counter-Wolf by another modder named Deschard.
King's CounterWolf features 30 new levels, playable on the first three episodes plus E4L1. Many graphics have been changed, with the main inspiration being the popular first-person shooter Counter-Strike.