Just for central reference (since lately some people have been asking this question, and this way I avoid writing the same every single time and link them here instead):
- To use the oversurrections you must first get the Oversurrector itself (but I guess this one is obvious)
- After getting the Oversurrector, you need a weapon to sacrifice
- The Ovesurrector is one of the many weapons that replaces the Redeemer in a random matter, so look for the places in the maps where super weapons spawn (such as Megaton, UltimaProtos, Nuclear Launchers), since there's where you will find the oversurrector
- If you are playing a practice session (offline play against bots or monsters), and you wish to "cheat" around the game to get the oversurrector immediately, open the console (using Tab) and type the following command: summon NWTheOversurrectorVIII.TheOversurrector
- If you wish to bind a key to it to be even easier, for example the X key, the console command is: set input X summon NWTheOversurrectorVIII.TheOversurrector
Have fun