Whenever a zombie’s Headcrab is both killed and detached from the zombie, it always falls straight to the floor as if dropped. This is especially awkward when using a shotgun to blow the Headcrab off of a zombie. I believe Half-Life 2 used additional code to artificially create a big physics impulse any time this happens, and this code is apparently missing or broken in Black Mesa. This is one of very few remaining issues that’s been bothering me in the latest version of the game, and it would be a greatly appreciated fix. I think not having the Headcrab come off at all would be preferable to it falling straight down through the zombie every time.
So glad that someone actually reported this, I’ve been thinking all this time that it was my imagination or I was just too stupid to properly score a headshot.
I believe it was like this in the mod version as well. The body of the zombie seems to properly react to the weapons however, but the headcrab, once it’s killed, just falls off like a rock, no matter what weapon I choose.