The mystery of Half-Life gameplay in the TV show "Lost" S1E21

In the TV show "Lost", episode 21 of season 1, somewhere around 12:15-12:30 we can see a guy playing Half-Life 1 for a few seconds before it goes off-screen. It would seem like a normal HL1 gameplay but as an old time fan of the Half-Life universe I watched this segment a bunch of times on repeat until I noticed something weird about it...

YouTube link to the portion of episode.

\"Lost\", S1E21, around 12:20

I examined the map where the gameplay segment takes place, launched my Steam PC copy of HL1 and found it in the game. It's the map c1a4e, the section of Blast Pit where we need to start up a huge fan which propels us upward where we need to break a few wooden planks to go even higher into the vents with some headcrabs and even more wooden barricades.

I'm standing at almost the exact spot as in the TV show

Here is the list of things that I found really weird about the gameplay segment in the TV show:

  1. The person in the TV show is fighting two zombies in a rather weird portion of the map. You enter this portion of the map from the door on the right and the two zombies are standing right in front of it (as you can see in my screenshot). While you can run past them before they even react, players are more expected to fight them before even entering the pipe area since it offers the protection in form of the door which the zombies cannot open. But let's assume you ran past the zombies. This is where things get really strange: the zombies cannot follow you anywhere farther than the rectangular entrance part. They might try to close up but they won't follow you all the way to the ladder yet the player in "Lost" is facing them in the "illegal" location.
  2. Right before the gameplay shifts off the screen you can hear a Houndeye sound. There are no Houndeyes in this map in a vanilla game, or at very least I wasn't able to find anything.
  3. It appears that the person in the TV show is playing on a console but the in-game user interface seems to be that of a PC version. For reference, the console versions have much larger numbers and symbols on the screen and they all use the HD models (correct me if I'm wrong).

So far I have three clues about what is actually going on:

  1. The TV is playing a video of HL1 gameplay recorded on the PC version. The Houndeye sound was edited in to make it feel like there is more action going on. This doesn't really explain how zombies are walking and chasing the player on that ring-shaped ledge.
  2. This is a video of the PC version gameplay but the recorder decided to mess around and rearrange the enemy selection and spawn. But why would they go such extra lengths to record a little piece of gameplay that would be on screen for just a few seconds? The zombies walking on the ledge is still strange.
  3. The TV is showing an obscure beta/pre-release/early release version of HL1 where gameplay in that section of c1a4e would've been different. The only one that I think matches all the criterion is the Half-Life WON version. I haven't checked it because my laptop can't run it reliably for some reason so if you have it functioning properly please check it for me and everyone else who is curious about this.

What do you people think about this?

P.S. I apologize in advance if I broke any of the rules, this is my first post on Reddit ever.