This is a really great fun film that deals with some of the aspects of time travel into the past. If one does anything to alter the past while there, what will be the effects on the future you knew? No hint of an explanation is give as to what could have caused the, I guess you could call it, 'time storm.' But the film does have has some very interesting twists and a cool ending. Not only that, but the flight sequences of the F-15s and the dogfights between them and Mitsubishi Zeros are just plain fun (from a modern day American perspective). Someone said that they are the best shots of an F-15 in action prior to Top Gun. Ever since I was a youngster, I wondered what would happen if you could transport a battleship or aircraft carrier back to say, the Revolutionary War era. Final Countdown comes about as close to playing with that idea as I expect to see.