When China White and The Hood are fighting, China is barefoot. When McKenna shows up, China is wearing her heels again.
The "Scylla" monster, which turns out to be a Russian made S-300 missile system, is shown as a lot smaller. The real thing is actually immense - only the S-300 missile is actually 7 meters (23 feet) long. In the episode the carrier is shown as a short range anti aircraft platform on tracked APC platform, meanwhile the real S-300 is carried by the vehicles, specially made for carrying the S-300 missiles.
The sign for "The Bludhaven APT" is reflected in the window, without the words being reversed.
Oliver asks McKenna if "Fall Out Boy" were still "cool" and she replies that they broke up. The band made very clear that they didn't break up in 2010, it was mere a well deserved break. Furthermore at the time this episode aired (December 2013) probably as well as when it was filmed, Fall Out Boy were back together again.