It'd require a little bit of programming. Each monster has got a 'classification', which can be one of the following:
- CLASS_NONE
- CLASS_MACHINE
- CLASS_PLAYER
- CLASS_HUMAN_PASSIVE
- CLASS_HUMAN_MILITARY
- CLASS_ALIEN_MILITARY
- CLASS_ALIEN_PASSIVE
- CLASS_ALIEN_MONSTER
- CLASS_ALIEN_PREY
- CLASS_ALIEN_PREDATOR
- CLASS_INSECT
- CLASS_PLAYER_ALLY
- CLASS_PLAYER_BIOWEAPON
- CLASS_ALIEN_BIOWEAPON
- CLASS_BARNACLE
So, you could download Solokiller's updated HL SDK for Visual Studio 2019 and change every
CLASS_PLAYER_ALLY
for example, into
CLASS_HUMAN_MILITARY
, then compile the .dll files.
Or you can just edit the monster relationship table:
Alternatively, you could probably use Spirit of Half-Life 1.2, which allows you to set the classification for each monster individually, in the map editor. (though, it has a tendency to
break other things and crash more often than vanilla HL)