When Shane is using the Peter Panda Dance to get past the security to the program Ghost, he steps back one step to avoid a blade that comes down in front of him. You hear him say, "One step back," but his lips don't move.
Classified information can never be viewed outside of a cleared area - especially not in public, as when Shane looks up information on the housekeeper while in the home, or when he looks up information about the principal while out on the playground. This would be considered a serious security breach.
In accordance with US Armed Forces dress code, a plain white t-shirt is considered as 'underwear'. Due to this, Shane, a strongly devoted soldier, would not wear one as an actual shirt if he were in the military.
In the opening sequence, Lt. Shane Wolf is briefing his SEAL team about their mission. At the time, he is wearing an earpiece in his left ear. After his line "We are SEALs, and this is what we do!" he puts the earpiece in again.
When Shane and the Fireflies enter the kids play area, you can see a mother try to pull her kid out of a ride. In the next shot, we see the same mother and child walking behind them, but when we cut back to the play area, the mother is still trying to get the kid back out of the ride.
In the chaos scene, Peter is standing in the fish tank wearing a red cape. In one shot the cape is half out and half in the water, then in the next shot it is all in the water, and in the rest of the shots it is back to half and half.
When the police are chasing the kids in the mini-van, Lulu says she is parking and immediately does a 360-degree spin to get next to the curb. However, in the wide shot, the mini-van clearly stops about five feet short. Only in the close-up does the van end up right on the curb.
The US Government car used in the last car chase has a speedometer where the large numbers are in kilometers per hour, and the small ones in MPH, consistent with this film actually being filmed in Canada but not correct for a US Government car.
When the family and Shane Wolfe are in the arcade you can see an Mortal Kombat 2 machine, later when Shane is getting the kid out of the balls you can see the screen on the MK2 machine and it shows the text and logo for Mortal Kombat Trilogy, which was only released on home consoles and was never in the arcades.
In the end scene when Captain Fawcett and the Koreans are being arrested they are being arrested by the FBI. However, as Captain Fawcett is in the Navy and the case is related to the navy, then NCIS would've been the federal agency involved in the arrest.
When Seth heads upstairs to the bathroom when Shane is handing out the tracking bracelets, he is barefoot, and when he exits the bathroom, he is wearing socks. However, he is upstairs about two minutes, giving him plenty of time to put on socks.
When Lt. Wolfe discovers that Seth has gone out the window he tells Zoe to watch everyone and to alert him if anyone comes within 40 clicks of the perimeter. 'Klicks' is military jargon for kilometer so in reality he's telling her to warn him if anyone comes withing 40 kilometers of the house.
The goof items below may give away important plot points.
Near the end of the movie, Shane and Lulu salute each other. When they do, they put their hands in the middle of their foreheads. Even Shane, an officer in the Navy, does then, when the Navy salutes with their fingers just touching their eyebrows as they salute.
When fighting the Koreans in the kids' room, Shane pulls the plastic crawl tube over the Korean's head pinning his arms down and to his sides with the batons pointing down. In the next shot, the Korean's arms are up with the batons pointing up.
At the end of the movie, after Claire joins Shane at the side of the stage during The Sound of Music (1965), it switches to a wide shot of the crowd applauding. Claire is seen in the crowd. It then cuts back to Claire and Shane at the side of the stage.
At the end of the movie when the Plummers are outside and the police come, the three cops on the left have glasses on, and the three on the right do not. Then when Mr. Chun says, "Drop your weapons!" the middle cop who was wearing glasses, isn't wearing them anymore.