It's all very simple. Kill other players Grab their heads Carry them noggins to the altar where the gods will reward you with frags.
HeadHunters 2 v2.5 UPDATE This file contains maps that were not included in the 2.0 pak, as well as the HHctf maps. It also contains textures that are necessary for "optimum visual performance" This is not the complete 2.5 pak and is meant only for those that just needed the newest stuff. For full information and docs, check out hh250manual.html