***PLOT SPOILER REVIEW***
As a former submariner who rode these old vessels I found this film fascinating. One story was that the US sunk this ship. This movie presents a different version.
The story is simple. The KGB goes rogue with a submarine with the intent of launching a first strike at the US, making it look like China did it. The film creates characters and internal conflicts to make the story interesting.
Kudos to the film for getting the submarine terminology and capability correct. This aspect was more realistic than most sub films.
There are some problems with the basic scenario. First off in 1968, China had only one Golf style submarine operational. It did NOT have launch capabilities. They wouldn't develop that until 1970. The second problem is that nuclear bombs have signature. We could figure out the difference between a crude Chinese graphite reactor bomb and a slightly more sophisticated Russian bomb. So the premise of the film while interesting, doesn't seem plausible.
Another film goof was when they encountered the USS Skipjack. The Skipjack was stationed out of Norfolk and operated in that area in 1968. The submarine in the Pacific was the USS Swordfish, i.e. a Skipjack class sub, but not the Skipjack itself.
The actors did what they could with a dry script. Landlubbers may find this film a complete bore and rightly so. We already know they fail. Extras include a talk about the real incident on which the film was based.
Parental Guide: F-bomb. No sex or nudity.