Well let me get straight to the point Hangover 3 is no where close to the earlier two parts of the series it certainly has its moments though.
The story goes like this Chow (Ken Jeong) has stolen goldbricks worth 21 million from Marshall (John Goodman) and in order to get back those 21 million Marshall kidnaps Doug (Justin Bartha - yes this time he is kidnapped for real) as he thinks its only the WOLFPACK that could find Chow. From here Phil, Stu and Alan (Bradley Cooper, Ed Helms and Zach Galifianakis respectively) begin there adventure.
The main problem with Hangover 3 is that the initial half of the movie lacks the zing and the fun that the earlier two parts had in fact at some stages you question yourself whether this is really a Hangover movie. But once the movie shifts back to Vegas it finds its rhythm and the directors suddenly seems more assured in what he is doing (it is as if he back playing on his home turf).
Now coming to the performances Bradley cooper, Ed helms and Zach Galifianakis all return to their respective characters and they exactly know what they are doing you can literally see how comfortable they are retrieving their characters. They are one of the main reasons why you could scrap through the initial half of the movie.Melissa McCarthy is adorable playing the love interest of Zach Galifianakis, the scene where they meet for the first time would certainly bring the house down. But the main star of Hangover 3 is Ken Jeong, he was impressive playing the itsy-bitsy roles in the earlier parts but here he gets a meaty role and he is awesome through out. Heather Graham and John Goodman do justice to their parts.
On the whole Hangover 3 is movie which had a lot of potential but was let down by a weak story and poor screenplay for example you expected sparks to fly when Chow and Marshall would meet at the end but the scene ends up so abruptly that you are left asking for more. The last scene of the movie is terrific and it also brings back memories of the prequels.
With this the Hangover series comes to an end and like Batman, Harry Potter and The Twilight this to falls short of your expectations may be it is because of the standards setup by the previous movies.
Anyways you can go watch this movie if you have nothing better to do at the weekend.