Goofs

The bandage on Barnes' neck is nowhere near the point where the spike was inserted.

When Sid steals the police cruiser and dumps Parker off he spins and does a 180, while taking off the light-bar on the cruiser is missing all but it's outer rotating lights but when the cruiser is approaching the tanker for a standoff with Parker all the lights are intact and functioning.

As Madison Carter (Kelly Lynch), is trying to free Parker Barnes (Denzel Washington) from the virtual world at the end of the movie, Barnes' Neural Sens. meter clearly shows at 800 percent, and climbing. The next shot shows a close up of the meter and it is only showing 689 percent, and it climbs up to 800.

SID tests his pain response by cutting the tip of his finger off. When he raises his hand to taste his "blood", the entire finger is gone.

During the chase which leads into the final fight between Barnes and Sid, Barnes randomly gets a nosebleed before even being touched, right before climbing up the stairs at Sid.

When the computer system is reciting chess moves, it mentions "rook to pawn four". Unlike the other chess moves that are mentioned (such as "bishop to rook seven" and "queen to bishop seven"), "rook to pawn four" has no meaning in chess because there is no "pawn" column.

The "video deck" Barnes uses to play the nightclub attack video is in fact a Pioneer PD-F51, which only plays audio CDs.

After Sid's hand is blown off by a security guard's shotgun in scene at the fight arena: He jumps the fence to escape the ring after he spots Barnes, and you can clearly see the fact that a 'hand' is still present by the way the actor (or stunt double) uses that hand to help hop the fence.

The needle that inserts the tracking device into Barnes' neck clearly slides backwards into the device, making obvious the illusion of sliding into his neck.

On the roof top, when Parker tells Sid that they're back in the box, the make-up on Sid's chin is peeling.

Glass is mostly silicon dioxide (or silica), silicone is a synthetic polymer which contains silicon along with carbon, oxygen, hydrogen etc. So regenerating body parts with glass alone is just not possible.

When Parker is being injected with the transmitter it is being physically placed behind his left ear. However, the monitor shows the injection taking place on the right hand side of his head.

After they have reinserted Sid 6.7 in VR, when Sid throws Parker from the rooftop, you can clearly see the wire on Denzel Washington's back.

The safety cable is visible on Barnes' waist during the fight on the ledge of the skyscraper.

Parker Barnes is arrested for allegedly shooting and killing SID's hostage at the train station, and later he is accused of killing the policemen who were taking him back to the station after SID murders them and "frees" Barnes (because he wants to see Barnes die a painful death when the satellite-linked chips explode in his brain). The problem is that both of Parker's alleged crimes are not plausible at all; if he shot the woman it would be obvious from the pattern of her wounds (since he was firing at SID from the front and SID fired at him, and shot and killed the hostage, from behind her) and he had his gun taken away and was handcuffed by the police before SID arrived for the murder/set-up.

When Madison and Barnes enter one of SID's crime scenes Madison sees "Death to the pigs" written on the wall in blood and claims that this is what was written on the wall following the LaBianca murders. It was actually "Death to pigs" that was written on the wall in blood following those murders. Death to the pigs was the title of a book written by Benjamin Peret.