This is the Re-imagining of the Classic Doom Weapons pack: "Doom: mega Weapons Pacl"
You will need GZDooM or Zandronum (Preferably Zandronum) for this mod. To download Zandronum go to Zandronum.com or Zdoom.org and get the latest releases of either sourceport. After that, extract The sourceport into any folder you wish (Not system files damnit don't be stupid ofc). Then, Copy your Doom IWADs into the Folder where you put your sourceport. If you bought doom from steam, it should find it automatically. If you don't have doom, then I suggest using Freedoom. Its a free first person shooter running on the doom engine so if you don't have doom, Try FreeDooM instead. After that, Unzip this mod into the sourceport folder and drag and drop the .pk3 file onto the sourceport's .exe file. After that, just choose the IWAD and press launch. You should be ready to go after that.
