This is without a doubt the best submarine thriller of the 80's. Possibly the best thriller of the 80's. Connery and Baldwin play their roles spectacularly. The plot builds pulling you in and wont let go until the final scene. On top of all this the musical score, which includes Russian singing, is wonderful.
Only complaints I have: Some unnecessary swearing (They always seem to have James Earl Jones doing this ie. Field of Dreams) including the taking of God's name in vain.
I give this a PG-13 because of swearing and some intense violence including a murder by Connery at the beginning, which you find out later was necessary for the greater good. But this is way too intense for youngsters.
Definitely watch this if you're into thrillers.