The Hangover Part III punctuates the run of one of the best R-18 comedy franchises of the last decade. I feel its a bittersweet goodbye as this sequel breaks the mold of what made The Hangover a classic and its follow-up, The Hangover Part II a solid movie.
At the center of the movie is Alan (Zach Galifianakis), the eccentric member of the Wolf Pack. We see less of Phil (Bradley Cooper) and Stu (Ed Helms), and I think it's a bummer because Galifianakis' batting average for hitting home run gags and jokes plummet in this movie. Thanks to Melissa McCarthy's Cassie, Zach becomes a bit more bearable.
Apart from deviating from the Hangover formula, I also feel the movie exists to tie the semi-loose ends of the first two movies and provide an acceptable closure and not to really excel in any way. It also says something about the movie when the funniest scene is the ending hangover scene.
The Hangover Part III is a good comedy, decent action film, and pretty OK finale to a franchise.