Shortly after Capt. Woodward debriefs Jackson and Armstrong in his office, Armstrong emerges from the room in front of Jackson, despite them leaving in the reverse order.
When Joe and Jackson jump off the cliff into the awaiting motor boat, the fall far from each other, and with a lot of momentum, yet when they are shown landing they are almost touching, and easily drop into the craft with a soft landing.
In the beach brawl scene, when Jackson leaves the boat and goes looking for Joe, he has no shoes on. After he finds Joe and both are running for the boat, Jackson has black gym shoes on, they can be seen while running and before jumping for the boat.
When inspector Singh and his assistant leaves Capt. Woodward's office after the talk about Taylor's death, Singh puts his hat on. On the next shot, he can be seen putting his hat on again.
Joe throws a sword at a ninja who shoots arrows at him from atop a boulder, causing him to fall off and hit the ground. However, the ninja falls in a way that would have him landing on his head, yet when the camera cuts to a shot of the landing, he lands on his back, making the shot uneven.
There are numerous errors in procedure during the meeting with the CO in the beginning of the movie. The army salutes its superior officers even indoors. Also instead of going to attention they go at ease. Even then there's a mistake as Joe goes at ease with his hand in front of him instead of behind.
Joe and Curtis obviously borrowed their Dress Blue uniforms from Staff Sergeant McDonald. Provided they also borrowed his ribbon set as well, both Joe and Curtis are wearing different ribbons from one another. Furthermore, the only row of ribbons that do match between the two of them is the bottom row, however they are in a different order which would be unlikely even if the two sets of uniforms actually belonged to them as ribbons and metals are arranged by precedence.
Near the start when Jackson and Armstrong leaves Capt. Woodward's office, it can be clearly seen that Guy Pringle, Michael Dudikoff's stunt double, plays Dudikoff's role for a brief moment.
The bombs that Professor Sandborne detonates in the lab supposedly destroy the entire lab, but it's clearly obvious from their explosions that they only flash brightly for a moment, and are pretty much contained to their respective cells. Their flames don't even touch Sandborne or the Lion.
Throughout the film, people are slashed with swords and killed, yet their clothing remains intact.
Shortly before the ninja is dragged by the pickup truck driven by Joe, he throws a grappling hook towards the rear of the vehicle. The rope clearly falls short off the truck, yet in the next shot it lands precisely and grabs its back corner.
During the bar fight while rescuing Alicia, Charlie gets thrown against the bar where a woman smashes a bottle over his head. She is impatient for her cue and reaches for her bottle twice before she is supposed to. Finally on the third time she smashes the bottle on his head.
At one point Joe and Curtis are wearing the US Army Class A service uniform. They wear identical ribbons, and both of them wear their ribbons in the incorrect order. The correct order would be the Army Achievement Medal by itself, centered on the second row, with the bottom row consisting of the National Defense Service Medal, the Army Service Ribbon, and the US Army Overseas Service Ribbon, left to right (as you face it) in that order.
Both Joe and Curtis wear a ribbon-only version of the National Defense Service Medal. Assuming the movie takes places in the same year it was released (1987), and assuming that Joe and Curtis enlisted around the time of the previous film (1985, very likely considering their low rank), neither of them is eligible for the National Defense Service Medal. The National Defense Service Medal is only awarded to US military service members on active duty during a time of war. Since eligibility for the medal ended with the conclusion of the Vietnam War in 1974, and the next period of eligibility would not be until 1990 with the start of the Persian Gulf War, neither Joe nor Curtis would be eligible for the medal.