Yeah but you were also just walking around by yourself. I wonder if they could maintain that visual fidelity with enemies and combat and scripting going on. Having said that, Valve has a lot of great programmers on staff so I don't doubt a new engine/tools is in development. They hired a lot of heavy duty graphics guys…
UnrealScript is completely optional, it's just a script layer on top of C++ code. It's generally used for gameplay code that doesn't need to be exceptionally quick, and it's the best place to store data structures / values since it offers very short iteration times; building a large unrealscript package takes around 30…