See part 2 here: https://youtu.be/Gy6L-Ozt1Qs
For those of you who don't have time to play it, I played through it again the other day for you and will try to summarise each of its 18 chapters for you so you feel as though you have played it. I did it on medium difficulty, and it took 5 and a half hours.
0:00 - Chapter 1 - Point Insertion
2:55 - Chapter 2 - A Red Letter Day
4:15 - Chapter 3 - Route Kanal
7:17 - Chapter 4 - Water Hazard
10:29 - Chapter 5 - Black Mesa East
13:02 - Chapter 6 - "We Don't Go To Ravenholm"
17:34 - Chapter 7 - Highway 17
If you're looking for pure gameplay with no commentary then Bolloxed has a great video here: https://youtu.be/4vFZ7PZ0bwc