When Eddie gets the medical kit out of the Japanese bunker, the door (which has a rising sun painted on it) doesn't shut properly behind him, so Richie sees it when he turns around. He wasn't supposed to find out about the bunker until later on. The audience laughs and Adrian Edmondson says "There was a little mistake there. Did you spot it?"
When Richie is about to vomit on the Welsh cannibals for the second time, he is seen holding the garden hose for the vomit.