The article references a clip from that channel that was uploaded in 2019 and taken down via a DMCA claim in 2022.

Closely linked thematically, Pushing Daisies. Both are very strange and great.

Incredible performance from the lead. At times he had me in pain from laughing, other times from cringing so hard.

Nah. They are detecting the collision in order to push the player, so the engine is doing the work already. They could easily add an on_collision_player event in the NPC controller that fires at that point to handle NPC reaction.

The age of the engine impacts things like loading screens, poor use of modern hardware, etc. The 2004-era NPC handling is simply a reluctance to do any more than the bare minimum.