The size of the weather balloons changes dramatically any time there is a transition from an on camera ground shot to a CGI enhanced wide shot of a character floating into the sky. The ground shots are a smaller, smooth balloon, where the wide shot shows a balloon several times larger with visible ridges.
While Fish Mooney is speaking to Detectives Montoya and Allen in her club, the end of her decorative scarf changes from being over-top to being wrapped underneath.
One weather balloon cannot lift an adult up in the air. For an adult like Lt. Bill Cranston weighing 200lbs or more you would need around 35 balloons.
When Lamond is lying on the stretcher, the drip chamber of the IV tube is empty. This must have fluid in it for the IV to work.
The name Carmine ( a variation of the name Carmelo, both used in Italy ) is read with the "i" as in Indiana not as in "Iowa".