You mean...in the original, 'h' doesn't target hostile...and you can't shelton slide? Wow, the slide is one of my main tactics, and 'h' sure does save me a lot of trouble. You know, I think Hellcat's right...
Aside from up to date graphics and the ability to run it at full speed in whatever OS I want, the thing I miss most now when I play the original is semi-autonomous turrets, like the NPCs have.