When Steve is in the smoke shop interacting with the cashier, he begins to back away after telling her that people are dying. In the next shot he is back standing where he was.
When Dennis and Steve are in the bar, the beer bottles on the table change; from Steve's view there are two bottles, from Dennis' view there are three. Then, from Dennis' view, there are only two.
In the 29th minute Steve is wearing his paramedic badge, Dennis is not. In the next shot Dennis is wearing his badge on his jacket.
In subsequent shots, Hawking's leash changes distance on the floor when Steve reaches for it from the couch.
In the opening few moments, they sitting up in bed about to take the drug, the man's shirt is unbuttoned to the waist, a few moments later it's buttoned up.
When Dennis applies the "...dressing to a sucking chest wound," the wound is not at all of this nature.
In New Orleans, an ambulance has two, not three crew members.
A paramedic would not be wearing civilian clothes on duty, as Steve is in the fourth minute.
Steve and Dennis' ambulance has no ID/unit number visible anywhere.
In the 30th minute one sees an aerial shot of two police cars without any markings or insignia on the roofs, hoods or trunks; a fire truck, likewise, and an ambulance likewise (also, the roof of the ambulance is heavily rusted).
1h 28m As Steve crawls in the trenches over the body of the soldiers. One of the extras shifts his left then moves his hand to his stomach when he supposed to be playing a corpse.