Audio problem: Nick uses the periscope camera through the grate of the basement floor. There is first a shot of the camera poking out and that is followed by a shot of a hand-held screen accompanied by a camera zoom sound as he zooms. Generally the zoom sound would come from the camera itself rather than the screen and a camera that size is not likely to make a electronic zoom sound of that amplitude.
Other mistake: When Brando, Norton and DeNiro are at the table, DeNiro accepts the job and tells Norton the stipulations. When they first begin talking the ashtray on the table is empty, but when Norton is telling his story there is a book of matches in the ashtray, then later they are gone again. Notice, none of the three characters smokes.
Continuity mistake: When Norton gets the passwords for the new cameras at the park, there are three passwords. The first and the second have three digits, but the third password has four digits. But when Norton types the three passwords, the sound was for three passwords of three digits.
Factual error: When DeNiro scouts out the building by going inside, Ed Norton guides him via a handheld two way radio. Having been a Marine for 5 years and working with various high power communications gear, I have never seen or heard of a handheld two way radio that can talk to another radio that is underground and quite a distance away. Both of the radios were portable meaning they had small batteries powering them, not a powerful power supply. Handheld radios work on the UHF spectrum, which is line-of-sight. It is impossible for a UHF signal to reach a receiver by going through numerous walls and metal piping. Ever lose your signal on your cell phone when inside a building or tunnel? Same concept.
Continuity mistake: Near the end when Ed Norton's character changes and gets ready to leave with the gold staff, he puts the bag with the gold over his back first and then puts on his backpack. Later, when you see him running to the bus station, you see that the backpack is against his back and the bag with the gold staff is on top. This is also evident when he is talking to Robert DeNiro's character and he takes the bag with the gold off first.
Factual error: The computer hacker says: "I was cruising around Ironclad's server at the root cobol level. when someone counter-cracked me, hacked into my machines, my data. For three minutes, I was fully exposed." The term "root cobol level" is completely made up, and has no meaning to a computing professional.