Unfortunately, that impression is misleading. The film is not particularly a comedy.
Fortunately, the film is a very good drama. The shame is that the film was marketed as a comedy rather than being allowed to succeed on its dramatic merits.
Viewing the film, I was correct to suspect that the story is based on the writer/director's experiences working at Adventureland after he graduated college. The story is interesting and relatable. Some parts are funny; some parts are not. Ryan Reynolds, Bill Hader, and Kristin Wiig are funny, but the film is really about Jesse Eisenberg's character, the young writer-director working at an amusement part the summer after college.
I recommend the film as a drama, not as a fun comedy. Even Wikipedia's article about the film includes a section about the misleading marketing. See the film for yourself, but don't expect it to be Anchorman. Expect it to be The Squid and the Whale or Lost in Translation. Enjoy it, and don't be surprised.