Plot hole: This happens after Gabe has killed the guy in the cavern and is reaching for the radio. We hear Frank trying to reach them, so they must be on the same frequency. Then, Hal finds out that a bomb has been planted, grabs a radio from the bad guys and starts yelling for Gabe to get out of the cavern because of the bomb. Why didn't Frank hear any of this on his headset?
Plot hole: A nuclear armed stealth fighter is accidentally sent back in time to 1940's Nazi Germany. After the Nazis capture it, two days later they drop a nuclear bomb on the United States. There are several basic problems here. Firstly, if the Nazis captured advanced technology, wouldn't they spend more time taking the plane apart and interrogating the captured pilot? How on earth did they manage to train a pilot to fly the stealth in such a short length of time? And how did the stealth fighter manage to reach the U.S. from Germany when in-flight refuelling was unknown then?
Plot hole: It is firmly established in the last half of the film that movie characters and movie weapons do inflict damage and death in the real world. However, early in the film, a bundle of dynamite comes straight through the movie screen and explodes in the real world movie theatre. That quantity of dynamite should have gutted the theatre, easily; but, when Danny Madigan and Jack Slater cross from the movie world back into the real world, there is absolutely no damage to the theatre.Charles Austin Miller