The actors spent two weeks in an intensive SEAL-style "boot camp." In the end, it was actors versus SEALs in a final "war game" showdown. The SEALs are reported to have graciously said that the actors made a good showing for themselves.
Originally, the men were going to play touch-football. But Bill Paxton felt the scene was too similar to the volleyball scene in Top Gun (1986). So he suggested that they play golf instead. Most of the golf sequence was directed by Paxton with a second unit crew.
When discovered by a terrorist who tries to speak to him, Hawkins shoots him without answering, then says, "Boring conversation. Leader, we're gonna have company!" imitating a similar line by Han Solo in Star Wars: Episode IV - A New Hope (1977).
Despite those named in the credits, the film went through another draft by Kevin Jarre. In one draft, Hawkins (Charlie Sheen) sacrifices himself to rescue Curran (Michael Biehn), who ends up with the love interest. In another version, Curran is killed off rescuing some kids, and Hawkins and Claire Varrens (Joanne Whalley) are left to mourn his passing. Also in one of those drafts, Curran is an accomplished boxer who squares off in a fight with Hawkins, who's into karate. The golf sequence in the film was a concession when the film's leads objected to a Top Gun (1986)-style scene with knife-throwing contests and bikini bimbos.
In the wedding scene in the start of the movie it is "Prince of Denmark's March" which is played. It was also played during the wedding of Lady Diana Spencer and Prince Charles at St Paul's Cathedral in 1981.