Continuity mistake: During the sports scene at Central Park, the sky keeps swapping from slightly cloudy to dark grey to sunny... no continuity at all.
Continuity mistake: When Hercules arrives at the ballpark, the guy in a leather jacket moves closer to the iron pole on the left.
Continuity mistake: When Hercules overturns the cab, the light suddenly changes from daylight to dusk.
Continuity mistake: When Hercules is drying his chest on the boat, his hairstyle keeps changing between shots.
Continuity mistake: When Hercules talks to the messenger, he moves the curtain aside, and the window becomes visible. In the close-up, the curtain is covering the window.
Continuity mistake: When the bad guys chase the chariot, there are 5 of them in the car, 3 in front and 2 in the back. Suddenly, the bald man behind the driver is on the opposite side, and the guy he replaces has vanished, leaving 4 in the car. When the car arrives at Central Park, all of the 5 baddies are back in the car, but the actors are different: the chubby copilot with a hat is now a thin man wearing sunglasses, for example.
Continuity mistake: When the lady in the plane freaks out, check the position of the hands of the man sitting behind her and the papers he holds. They keep changing positions all the time.