I watched the video and failed to see a single thing that could be called impressive, just a bunch of skeletons primitively chasing the player character, and one clumsy giant. The tech demo looks like Aurora engine mod.
Emergent monster conflicts, like "leading one type of monsters to fight anothe type" was present even in primitive shooters from 90s like Doom, etc. (when they shot each other, they fought), or Strife, which was actually an impressive game for the time.