In B-1 Nuclear Bomber, you have to "fly" a B-1 bomber to it's destination, and destroy the target of the mission.
You input text commands to control your bomber's altitude, course, radar, weapons, and so on. And, of course, the USSR will try to stop you from bombing their targets, with an arsenal of MiGs and SAMs, and they are dealt with by the use of electronic counter-measures, evasive actions, or by shooting them down.
The game ends when it reaches a logical conclusion, either by deploying your bombs and getting far enough away, returning to base, or being destroyed. After this, you get a short summary, and an option to play again.