This addon replaces the enemy combine soldiers with the npc's from Halo: ODST. I need to say that I didn't create the models, I simply ported the NPC addon from gmod to HL2.
Create a new folder in "C:\Program Files (x86)\Steam\steamapps\common\Half-Life 2\hl2", and call it "custom"
unzip the file and put the folder "odst_combine" in the directory below
"C:\Program Files (x86)\Steam\steamapps\common\Half-Life 2\hl2\custom\"
Addon created by: Bulldog135789
If you have any questions, you can simply ask me here:
steamcommunity.com/profiles/76561198271257091/ or at firstname.lastname@example.org
To remove the Addon, simply delete the folder