Also, @2:28 scaring Barney with grenades or helping him clear the room will cause him to open the door. This skips the freezer section, saving 1m+.

In case you weren't aware, scripted runs of Half-Life aren't really much of a category. I'd highly recommend learning to bhop yourself and try your hand at the most popular, and competitive category WON Hard.

In terms of improving your route, Tryedz (current WR holder) has a fantastic, in-depth, but slightly out-of-date guide you can find here:

Nyu (current top 10) also has a guide, although I haven't personally watched it. You can find that here: https://www.youtube.com/playlist?list=PLVpriSp8rvGa-Pl9uynt0wtq7q8ooCuF5

Good luck, and welcome to the community.