l4dhunter_swep_v2.zip

This download looks like an addon. You need to extract the downloaded zip and put the addon folder in your Garry's Mod addons folder. You should end up with a directory structure similar to below:

• steamapps
  • common
    • garrysmod
      • garrysmod
        • addons
          • l4dhunter_swep <-- Addon folder!
            • e.g.
            • lua
            • maps
            • materials
            • models
            • etc

• l4dhunter_swep/
  • info.txt
  • lua/
    • weapons/
      • l4dhunter_swep/
        • shared.lua
  • materials/
    • models/
      • zombie_fp.vmt
      • zombie_fp.vtf
      • zombie_fp_NM.vmt
      • zombie_fp_NM.vtf
  • models/
    • weapons/
      • v_swipe.dx80.vtx
      • v_swipe.dx90.vtx
      • v_swipe.mdl
      • v_swipe.sw.vtx
      • v_swipe.vvd
  • sound/
    • weapons/
      • hunter/
        • growl.wav
        • melee.ogg
        • pounce.wav

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