Plot hole: The secret CIA base at Kamp Woody was underground. Kids searching for years have combed the camp, but never found it, but when Cody is going down the escalator, you can see bright skylights on the roof. If the sun is able to shine through, that means the skylights aren't hidden, and the kids would be able to find the camp.
Plot hole: When Cody first discovers what the explosive Mentos mints do, the explosions are just minor. Later on in the movie, the Mentos are treated as though they create big explosions. At the end of the movie, Cody throws a Mentos, which his brother licked on, out of the car and into a lake; the explosion was bigger than the explosion made when they were first used.