Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Use a text editor to edit the "gamerules.lua" file in the "/farcrydemo/scripts/default" folder. Find the following line.

"ai_to_player_damage = 1, 1, 1, 0.5, 0.5, 0.5"
and change it to :
"ai_to_player_damage = 0, 0, 0, 0.0, 0.0, 0.0"