Pifias

When Cash enters the tunnel at the beginning of the prison escape, he doesn't have the crowbar in his hands. Yet in the following scene, the crowbar reappears.

During the prison escape, on the roof while attempting to jump to the power line, the camera front view has Cash wearing a sleeveless shirt. When camera shot is on the back of them Cash (or rather his stunt double) is wearing a tee shirt with sleeves.

During the raid on Perret's compound, Cash is in the stairwell firing an automatic weapon that appears to shoot bullet holes in the wall of the stairwell. The bullet holes appear in different amounts and patterns between shots. Also, Tango has an automatic weapon and fires it right at the lower side of an office desk he has dived to for cover. The muzzle flash is clearly reflected on the side of the desk surface, yet no bullet hole damage occurs to the desk.

Cash is seen walking towards his apartment door with a handful of groceries. But in the previous scene, Cash had already parked his car in the garage and walked away with his hands empty.

When Tango is escaping from prison, he is running towards the ledge holding his belt in his right hand. The next shot when he is in the air, the belt is in his mouth.

When Tango gets dipped in the electrified water in the prison "welcoming committee" scene, a prisoner is holding on to the metal chains around him but somehow isn't electrified himself.

In the opening scene Tango swaps out the rounds in his pistol for presumably higher energy cartridges. Subsequent discharges are deflected off the windshield of the semi tractor. Later in this sequence the same rounds have sufficient energy to puncture the steel of the tanker.

He's more likely changing them out for LESS penetrating rounds as he would have killed the driver and passenger of the truck if they had penetrated the windshield. Windshields are also built to deflect and angled so it's not far fetched for the rounds to bounce of the windshield but still pierce the tanker.

After drugs are found in the tanker truck, an officer crosses from right to left carrying a PR-24 side handled baton turned in the wrong direction. The 'knob' should be near his thumb and the long portion of the baton near his pinkie finger.

Both Tango and Cash fire their weapons early on in the film but are immediately seen back at work. Police department policy requires officers who discharge their firearms to be placed immediately on routine, paid administrative leave while the shooting is investigated to determine if it was a justified shooting. This can take weeks and no officer would be back at work right after the incident. This is an artistic license that most if not all buddy cop movies employ.

At the beginning of the movie when the truck is bearing down on Tango and he fires at the truck, the windshield "spiderwebs", as it should, since it would be safety glass. However, when the two men fly through the windshield after the truck is stopped, there are no bullet holes in it and it is clearly a plate glass windshield (due to how it shatters).

When Tango jumps away from the blast in Wyler's apartment, the face of the stuntman is clearly visible.

When Tango drops from the wire, an extra cable holding him up at the waist can be seen falling down.

There is another mistake with the trucks at the beginning when Face slams the brakes and both guys break out the window, apparently he also put the truck in park or neutral before being thrown out of the truck since it does not move a inch after his foot is removed from the brake.

Obvious body double for Sylvester Stallone in several scenes including when he turns his Cadillac around in the desert and when he walks into the police station after his big drug bust.

When leaving the dance club, Catherine and Cash get on her motorcycle. You hear the motorcycle start and rev once, but Catherine's right hand is down by her side, not anywhere near the throttle (or the start button for most bikes).

When Cash is pushing a garbage can/truck in the prison yard, at the beginning of his escape attempt, the lower leg and foot of someone also pushing it on the far side from the camera can be seen, by the bottom right corner of the can.

When Tango & Cash Get arrested for murder,and you later hear the surveillance tape. The "victim" is killed with a silenced/suppressed gun. But when they get arrested neither of them has a gun with a silencer. Cash has a revolver with huge laser sight on. Tango has a revolver and an automatic for backup. But no silencer.

When they get arrested, Cash's secondary weapon is found on the ground with a silencer, he protests that it must have been stolen from his locker in that exact scene.

Cash claims the sights on his pistol were shifted, his gun is a Walther PPK/S which has fixed sights that cannot be adjusted.

Both Tango and Cash refer to Sokowski as both Matt and Max.