Tagline 'The Ultimate Nuclear Submarine Simulation', it's basically not a videogame, it's a hardcore simulator of the 688 (Improved) Los Angeles class of United States (SSN) nuclear submarine.
From the back of the box:
"Jane's Combat Simulations presents 688(I) Hunter/Killer, the most realistic submarine simulation ever developed for PC. Master the sonar and weapons control systems, learn to deevlop real target solutions and outfit your boat with the lastest advanced weaponry. Then use your skills to complete the tour of duty and earn your dolphins to become a true submariner."
The original release came with a 280 page thick manual, in detail handling all of the 12 stations you'll have to be able to operate. On top of that, as a modern submarine, you'll barely ever use your periscope and in game it's even impossible to stand on the bridge when surfaced. The 'action graphics' (you are able to use a camera view following the missile you just launched at your target) were under par for the time of it's release, but action graphics is not what this game is about. The user interface is great and so are your crew voices, which at times will be yapping over each other, in a realistic way.
There are three types of mission formats: Training, Single, and Campaign. Your mission objectives range from simple ASW interdiction, protecting Allied-flagged tankers, SEAL team extractions, running interference for Allied Battle Groups, to opposing enemy battle groups.