In the beginning of Half-Life we see that his suit is missing its helmet, which is why he can die to headcrabs, drowning, or toxic waste. If he had his helmet, he would basically be impervious to everything other than bullets and fall damage.
i’m mostly Anti-helmet due to the Half life 2 cover art having gordon without a helmet
but i also don’t believe that that’s the explanation for the headcrab gameplay mechanic since we’ve been shown that headcrabs can absolutely chew through helmets, with the existence of the Zombine being an example of this. (i’m assuming that the combine helmets are armored or made of hard materials)
There was a really good video about this somewhere on youtube. It’s extremely inconclusive with the most logical explanation being that at some point the helmet comes up for Xen, since it’s basically all but confirmed that you need it to survive in that environment.
I’m personally in the always helmet camp due to how often you get shot at, one stray bullet to the head and your 43 remaining HP are gone.
The way I’m interpreting this is that you think Gordon Freeman wears a helmet some of the time, but not all the time.