At one point, Raphael throws his weapons towards electrical cords that are out of control, thus pinning them to the ground to immobilize them. In the very next shot, both weapons are seen in Raphael's belt.
The turtles pop out of the manhole between Irma and Shredder on the sidewalk when they encounter Shredder in front of the Ice Cream shop. It wasn't there when Irma is seen coming out of the Ice Cream shop. Then when the enlarging ray zaps Irma, the manhole is behind her and in front of the entrance to the Ice Cream shop.
When Vernon is running with a camera to get a shot of giant Irma, his pants are purple, but when he turns a corner and sees regular size Irma, his pants have changed color to blue.
When the turtles encounter Irma while they're on top of the Channel 6 building, Irma cries in fear that she won't return to normal size. After Michaelangelo upsets her more and she says "big mouth", her mouth doesn't move with the dialogue.
At the beginning, the man tells April they are live in 20 seconds, but they actually go live in only 7 seconds.