So, for those who didn't watch the show (just in case). Do I need to watch it first? you are suppose to, indeed, for getting all the reference that the movie is pointing out that are quite a lot and important ones, since this is more like a sequel of some arcs, and even a prequel for some other arcs of the Melancholy of Haruhi. But is not a must, they quite explain everything fine in order for you to understand what is going on, is not really a script for brilliant people. Just understand what the premise of Haruhi is all about and you will have enough.
Also, I do not plan to review the show, because I really don't think there is something special for me to watch it for the second time, as results I don't remember enough to be able to make a decent review. But the movie is the only thing that is somehow worth it watching it twice or more, maybe in a far future but I wouldn't mind giving it another try.
As for why The Melancholy Of Haruhi doesn't worth another try. Well, as for an actual good romance between a total bitch and a fun guy, I will watch Spice&Wolf, as for time travel I would choose Higurashi or Steins;Gate, talking about time, but more specific, as it goes for an endless eight were you wouldn't think you waste your time, Tatami Galaxy is the one, as for the human god matters Serial Experiments Lain deals with it a lot more better, but in case some doesn't like the slow pacing of it I would recommend Paranoia Agent. As for Moe, I could easily check another work of Kyoto Animation and I would pick Hyouka, which is also a school slice of life, but with more character depth. So This show has a cool premise and stuff but it falls in the mediocrity because it only focus in selling moeness.
So I would recommend the movie for the presentation, as for the whole franchise of Haruhi, it goes to those who love moe and school rumpus. And for those who are interested in just watching it for the impact it had and still has (with less force), that's why I watched it.
Well, the movie is LOOOOOOOOOONG, about 2 hours and a half, with a pacing that goes the speed of snail most of the film, and other times is just too rushed. And everything is narrated by the protagonist Kyon, from "how do the toilet paper goes" to "what is the meaning of life?" sometimes necessary, but most of the time, just damn obvious, there is even a scene where all the train of though is there for you to understand what is going on, and noooo, you need an auto-character analysis like a cheap version of evangelion to understand what was already there, just for the sake of: Look how deep this movie is.
Aside from that, the plot... is interesting I won't deny, it is truth that is full of popular cliché and inside references, Although it would surprise me if someone didn't knew this when decided to check it out. It is pretty much "Back to the future" with moe, the problem is, that even if the great presentation of the animation, music and plot formulas about time traveling and stuff, were there to support the film, they didn't do much since the movie should have called Kyon Nothingness, half of it is Kyon doing nothing, narrating, suffering, being a dick (and he says he has control and that he is no like Haruhi, maybe in the show but here he really is an asshole that doesn't think very much even when he seems to be thinking everything.), and when he does things is because of coincidences and because everything happens just in the right moment, but he doesn't really do much, and he is the main protagonist.
So just the presentation is worth it, since even at how bad some aspects were managed, they know how to play with your emotions and get you in the mood of the film, at the end, this is Kyoto Animation, that's what they do.
Even when I said Kyon was a dick... he is the best character... I didn't remember how lameish everyone else was, I remember they were one-dimensional, but not this much, and one of the causes, is that everything is so Kyon-Centered that they don't care about what is going with anyone else, the others are just like cartons-figures with a moe personality, even Haruhi whose name is one the title. Somehow the dullest character of the TV, Nagato, here was the one they give more development aside from Kyon, pretty pretentious and it was far from being a big thing, so no credits.
Nothing odd with the sound, the voice acting was cheesy but appropriate for the characters, even after hearing 2 hours of narration, it was good voice acting, and the Soundtrack was superb! this is the reason I watch it twice and I could watch it again. such a shame that they barely use it, I was like, where is the music?, where is it!!?, oh, here it comes, oooh yeaaaah, and it's gone...
The animation is awesome, 3D effects were sometimes weird, but it was Awesome!
As for the enjoyment, it was good; great music, great animation, cool concepts and good presentation, no doubts why this and the K-On movie had an bunch of overrated hype. I just wonder why the aliens agency didn't take out the powers of Haruhi, and erase everyones memory since the beginning so they wouldn't have to worry so much about time continuity, cheesus!