Goofs

When Charlie mounts the tank, he's wearing a khaki green t-shirt under his shirt. But when he sits in the driver's seat, it changes to a Puffin Marmalade t-shirt.

Charlie wears the same pair of blue-white sneakers along the entire movie. But when he arrives on the island, and spots an egg, he's briefly seen wearing a pair of rubber boots while walking in the water.

How can the "medicine man" have glasses at all, since the island is supposed to be hidden and relatively undiscovered from civilization? (Unless of course he took/found it from a dead soldier who was once stationed there - they say that the US and Japanese fought on the Island))

The rifles Kamasuka fires by pulling strings tied to them are Lee Enfield .303 SMLE rifles. They were used by the British army in WWII. Neither the Imperial Japanese Army not any branch of the IS military used them.

When Kamasuka throws grenades he arms them by pulling arming levers as in Western grenades. WWII Japanese grenades were armed by striking a spring loaded detonator on a hard surface, not by pulling pins.

Many of the blows in the final fight scene obviously miss their targets and hit only air.

When Kamasuka chops a rifle in two with his sword it is obvious that it is just constructed of painted wood.

When the heroes return to the island and crash land the plane, you can see the steel wire pulling the wrack.

In the scene where the natives lead Bud and Terence to the jap tank, they both wear parts of US uniforms they took from the abandoned WWII US military depot. Hill's shirt has US Air Force written on it, which is incorrect, as the USAF didn't exist before 1947, two years after the end of WWII.

Cameralights are reflected on the surface of the tank once it gets out of its hiding place. Also, you can see the lights reflected in the glasses of the "medicine man".

Under no circumstance would a Marine Major ever wear a New York Yankee Cap among his men and in front of civilians, and therefore, technically, be out of uniform.