which makes me think about a remake of unreal 1. same gameplay, same levels, (almost) the same experience... just with up-do-date graphics...
i know it wouldn't be the same experience. not really. but dunno... i think it could be worth a try.
btw, do you remember that unreal had various ways to solve the game? as far as i recall, you were able to go different ways, (which led you to alternate levels at some time) which gave you quite a lot freedom.
correct me if i'm wrong please.