This movie was... a mixed bag in my opinion. It had some fun moments, I liked the scenes with Jirachi in general, because it's such a cute Pokémon. Seeing Absol was cool too, especially since it's grown to be one of my favourite Pokémon lately, and I think the movie shows really well how Absol get their bad (and somewhat undeserved) repution for being a disaster Pokémon, like it's always mentioned in the PokéDex.
The ending however was really bad... like they didn't know what to do with it, so they just threw random **** together and hope for the best. I mean, we get a mega-sized Groudon out of nowhere, that isn't really like Groudon but looks like one, and it has a bunch of tentacles for no reason that rape everything in sight. Then we have dragons flying around, trying to escape the tentacles, and somehow Jirachi still plays a role in all of this.