I finally got a chance to watch this movie. One thing I do want to note is that my review is based off of the JAPANESE VERSION of the movie, not the English dub. I can't stand the English voice actors for the characters ever since they were changed sometime after Hoenn, I believe, so I haven't watched the English dub since. I will still use the dub names, since people are more familiar with those.
Let's get started.
Five strange pokemon, Genesect, show up searching for something while we see Mewtwo (who happens to be different from the Mewtwo in the first movie) trying to test how far and fast it can go.
When Mewtwo comes upon the Genesect and save them from an avalanche, the smallest one reveals that they're looking for their home, though the red/shiny Genesect (obviously the leader) wants nothing to do with Mewtwo and attacks before they run off again.
Meanwhile, Ash and his friends have come to the Pokemon Hills; a location in an Unova city which will host a variety of pokemon in natural habitats for them. Upon exploration, they meet up with a Sableye and the small Genesect. Ash promises to help the Genesect find its home, but then the red Genesect shows up and attacks. Not only does it attack, but it controls the other Genesect to attack.
Ash and company are saved by Mewtwo (who can freely transform to Mewtwo Y), though Mewtwo's intention was to just save the pokemon.
Later on, Sableye comes to warn them that there's a problem in Pokemon Hills, caused by the Genesect.
Team Rocket makes its typical cameo appearance in the movie and then doesn't do much of anything. There are also the protagonists (Ash, Iris, and Cilan).
The only human character we're introduced to in this movie is Eric, the caretaker of Pokemon Hills.
There are the Genesect, of course; there are a total of five of them, each with a different Drive installed on their backs, and all searching for their home in a world unfamiliar to them.
The Red Genesect can somehow control the others and give orders, and is much faster than the others, as well (most likely why the Japanese title is called "Extreme Speed Genesect...").
Mewtwo makes an appearance, and had the same story as every other Mewtwo. Only this one has a feminine sounding voice, and can freely transform into its mega form (Y version).
The movie felt very reminiscent of the very first movie, particularly a later scene which involves a large fight between the pokemon (while the humans can only stand there in shock and sorrow).
While that could be considered a minus point, I felt it was a plus. It evoked quite a lot of emotion, and that entire climax scene was done very well...and this time, there wasn't a single battle-ender (like Ash being turned to stone, thank goodness).
I don't want to put in any spoilers, but there were a couple moments in the final battle which ran emotions very high, especially in regards to the small Genesect (the one who could be considered a main character next to the red Genesect). The transitions and the way the battle between all the pokemon took place and was resolved was certainly a huge step up from the first movie.
Not that the movie didn't have its falling points.
First and foremost was Mewtwo. Anyone who has played the Pokemon games (be it Gen I, or the Gen III remakes) know how Mewtwo was created, and that there is only one Mewtwo.
In the anime, we've seen three Mewtwo already: One in the first movie, one in the anime itself (which could be related; we don't know as I don't recall a definite conclusion on it), and this one. They all have the same backstory of creation and then eventually breaking free of their human captors/creators, as well.
The movie might have been a little better if it was the same Mewtwo from the first movie, in the least. The movies in Pokemon are great in that they flow with the TV show (unlike DBZ movies, for example, which make no sense in the timeline sans a couple of them), so it would have been better if this Mewtwo was the same one. That also breaks pokemon lore, and can only lead us to believe that Mewtwo was there just for the sake of the plot, or that there was more than one research facility which created more than one Mewtwo.
The second issue is that it was never explained how the red Genesect could freely control the other Genesect. In the games, a red Genesect is its shiny sprite, but in this case, it was to differentiate the "leader" from the others.
The third issue is in the animation, which was why I docked points. At times, the characters were animated quite poorly, and had lanky limbs (particularly Team Rocket, though Ash was seen with this bad quality of animation during one scene in the end credits, as well). The fights and battle animations were excellent, so I didn't take too many points off.
Overall, the movie was extremely enjoyable, and I would recommend it to fans of the series. I don't know how the dub was, but the original version is certainly worth watching.