When Liber8 hack into Kiera's CMR and control her, she shoots at Kellog and another programmer. When she first fires, the front of the handgun is clearly a 9mm Heckler & Koch USP. She turns around to point her gun at Carlos. It suddenly changes to a 9mm Sig Sauer. The most obvious difference are two sculpted lines on the USP's sides. The Sig is much slimmer and does not have the sculpted lines.
When Carlos talks to Kellog who is sitting in a taxi, the level of the window glass is lower when viewed from the outside than it is when viewed from the inside.
When Alec is defending Keira from a hacking attack, a cameraman can be seen filming behind Alec in his computer lab.