HL2 was a flagship for a newer game engine. The physics and details were amazing when it came out, and then you had other games and mods like Garys Mod that was just an amazing sandbox of the engine in the game.

From the tech side it was the heavy, and smart, use of scripting that made HL1 stand out.

With HL2 it was the added physics engine trough the change to Source, back then that used to be a big deal and whole gameplay mechanics revolve around that (gravity gun).

In that context, I do not really consider it that surprising for the next HL project to focus on VR because even early demos of that combination looked already very promising 5 years ago [0].

[0] https://youtu.be/-RehCTRrWM0

a good story will hook gamers all day every day. Between HL1 and 2, there were side stories that expanded the world. Let’s not forget the source engine powered counter strike and so you got half life “for free” or vice versa.

HL2 has dynamic gameplay and HDR and really just made the game play really immersive. From the agents that try to break down the door and all of the chains and razors shake as the walls rattle.. the deep black of the dark nights contrasted with the next morning when you’re on a boat getting attacked by a flying death drone. Or the massive walking robots that you fight along side Npc teammates that you legit feel bad for when they die. It was beyond well done, it set a standard for how cinematic gameplay should be done.

People will look back at Newell in 40 years like he’s Scorsese.