Use a text editor such as notepad to edit the "default weapon.ini" file in the "\damngame\config" directory in the game folder. Change the following lines as indicated.

PRM_DamageAI=(Value=(0))
PRM_DamageAI=(Value=(0,0,0,0,0))
MeleeAttackDamageMin=0
MeleeAttackDamageMax=0
InnerCoreDamageAI=0,
InnerCoreDamageRadius=0
OuterCoreDamageAI=0
OuterCoreDamageRadius=0
KnockDownRadius=0