The best thing you can do is destroy all the communications first to limit the back up. Mark every enemy, even the trucks that drive off stay marked when they come back or you see them somewhere else. Suppressed sniping, and blowing up radio towers and running off until alert cools down is what I did. If I got spotted I basically murdered everyone. Upgrading your D Walker is top priority as its the best getaway vehicle. The scouting head was supremely useful. I don't think it works for hostage extraction though, You can't toss them on it and drive away if I remember correctly.
The game on a whole is very similar. Later it will get a bit tougher with large armored vehicles and the damn chopper trying to kill you. But for most of the time its your own pace. Then there was one mission that I recall that wasn't your own pace and was very annoying. I remember having to follow a truck without being seen and also not letting it get too far away. I forgot why but I just remember failing it multiple times.