Chopper Commando came out in 1990, written in Turbo Pascal by one guy (as was the fashion in those days).
It's a very simple game with simple graphics, but extremely playable mechanics and a control scheme that takes time to truely master.
One of the things that makes it special is that the rules of the game change. You start off flying your powerful helicopter, but if it gets too badly damaged you need to eject and attempt to survive on foot.
You can explore the landscape this way (and find a few secrets) although you're a lot more vulnerable. If you can hold out long enough a rescue chopper will actually come and pick you up.









