Revealing mistake: When the kid is playing the Game Gear and says 'I thought I was playing Shinobi. This isn't Shinobi. Where's Shinobi?', there is no game inserted in the Game Gear.
Revealing mistake: When they are surfing using the boards they cut from the trees, you can see the ankle cuffs on the boards, clipped on to the actors. They didn't cut the ankle cuffs as seen earlier and when they are running to the sea they don't have cuffs either.