Pokemon the First Movie - Mewtwo vs. Mew Reviews
The basic plot of the film is Ash and his friends has to try and get to an island where a Pokémon tournament is supposedly held, but it's a trap setup by a genetically-modified Pokémon called Mewtwo. Mewtwo attempts to steal Pokémon from their trainers (including Pikachu), clone them, and turn Pokémon against humans because Mewtwo is a bad Pokémon who hates humans. Oh, and Pokémon are creatures that fight each other.
Pokémon: The First movie is just an extended episode of the TV show. It's a thinly-written movie where the second half of the film is just a bunch of Pokémons fighting each other. Watching this movie as an adult was cringeworthy. There's Pikachus slapping each other and Team Rocket disguising themselves as vikings with a cringeworthy Swedish accent. In the third act, characters preach that violence is bad, even though the franchise will continue with Pokémons fighting each other. Worse than that, Ash gets petrified and was revived through the power of tears.
For die-hard fans, Pokémon will forever be nostalgic. For everyone else, Pokémon is the perfect kids movie that doesn't age well when you're older.