[Max Lobovsky]

Both Unreal 2 and 1 are being discussed in this post, I think its important to know some distinctions.

First of all, Unreal 1 is dying. There is no development to the engine and most modding has come to a halt.

Though Unreal 1 would mean that the game would almost definitley be playable on most systems, that isn't because it can go lower than Unreal 2 in terms of graphics, but because it can't go as high. It is definitley possible to use Unreal 2 with the same level of detail (texture resolution, poly count, lighting mode....) as an Unreal 1 game and achieve similar performance.

Unreal 2 has built in support for vehicles and is much more able to handle non-human moving stuff. It is much easier to script the movements neccesary for a robot. Actually, I don't think U1 would even be able to do the job at all.