While mercenaries chase down Valerie and Jack with boats, Parker's pistol is shown to be empty in close shot (slide is locked to back-position). In the next cut the weapon is reloaded again (slide is where it is supposed to), but in the next shot immediately after it the gun is empty again.
In the scene after the mutants escape and one is seen jumping from a high platform Jason is seen holding a M4A1 rifle. The next scene he is shooting the mutant but is now holding a G36k
At about 37 minutes in, Valerie shoots a spear gun through the roof of the car and into the floor of the helicopter. The helicopter sifts tie car and carries it. That helicopter is not designed to lift heavy weights and there is no way it could have lifted that car and them in it. Even if it could lift that car, the hook was in the floor skin of the helicopter, which is thin metal and it would have ripped right out of it..
In the end scene when Jack Carver is walking away from the couple the sound guy and his microphone are visible on the boat.