Continuity mistake: When Stallone is told to climb up and retrieve the first suitcase of money, we see him reach a rather open landing with plenty of room to kneel and break open the suitcase. Once his partner (still below with the terrorists) screams "They're gonna kill you," and the terrorists start shooting up at him, the camera pans up to show him standing with his back to the rocks on a tiny ledge with barely enough space to stand.
Continuity mistake: Shortly after Frank is shot, Caroline Goodall's character checks the fuel gauge of the helicopter, and puts the kybosh on any ideas about flying around looking for the third case, as the helicopter only has enough fuel to get them down from the mountain. Later, John Lithgow, having kidnapped Janine Turner, flies around for ages, and the helicopter stays in the air for a surprisingly long time.
Continuity mistake: When Hal is on top of the mountain with the English bad guy and the guy with the tracker, the guy with the tracker tells the English bad guy to get rid of him quietly. 30 seconds later the same bad guy looks up and sees the English guy falling down the cliff having being killed by Hal. The bad guy has climbed down about 5000 feet in 30 seconds.
Continuity mistake: When the Lockheed Jetstar is flying, it has an antenna with only one vertical tip that looks like a shark fin. Once the plane is on the ground you can see that the antenna is different and has two horizontal tips, similar to those antennas seen on limos or on the 'Fokker F-27' / F-28 models.