Don't get me wrong; I love The Inbetweeners and the first film, but the second film definitely takes a step-down.
The first thing that is annoying is that this whole film in general isn't necessary. The first film ended perfectly and while a sequel would be nice, it kind of defeats the purpose of the first film. You could've watched the second film after the series and it would make sense.
Also, it just doesn't really hit the same as the comedy in the series and I think most scenes in this film are mostly done for shock humour. The plot with Will and Katie was really boring to watch for me and the only good scenes really were just with the four boys.
One thing I will credit this film for is for the scene where they are stranded on a desert without any water sources or food. It was very hard-hitting and interesting to watch. I never thought The Inbetweeners would provoke this feeling because they focus more on comedy, but it still fit in pretty well. But one thing that is annoying about this, is how they made us think they would all die. I mean, I think that's a bit extreme.
Mostly the reason why I think this film didn't succeed as well as the show and first film is because it doesn't really capture the same comedy as well. That doesn't mean there aren't any funny parts, but most of it is pretty unfunny.