What most people need to understand about movies is that not all movies need to have a strong plot or script to be good and enjoyable. They can be cliched as a 70's romantic movie and still be pretty awesome.
The movie takes place in the 2020's where an alien lifeform known as Kaiju emerge from the Pacific Ocean due to tectonic plates shifting and start attacking various countries on the rim. The monsters are huge and need to be taken down and what better way to do so than with giant robots loaded with various weapons? The nations of Pacific Rim collaborate to create the giant weapons known as Jaegers. Each robot is controlled by two pilots whose brains are connected through a neural bridge to share the mental load of piloting such a massive machine. Several of the main characters have their own demons and reasons for wanting to be part of this war and they all come together in order to save humanity.
While it is true that the movie lacks depth, it's not completely absent from it. Del Toro here focused on the message of how people have to put aside their differences and work together for the greater good, even going as far as sharing their thoughts and fears in order to pilot the Jaegers and they have to be in complete sync in order to be able to fight off the Kaiju.
The arcs of several characters were not detailed and were made on a need-to-know basis. Del Toro had to cut off a whole hour of material from the movie since he only wanted it to be 2 hours long and wanted to target younger viewers. He felt it was not crucial to add the extra material as it just described the characters' arcs in greater detail.
The acting was above than average considering this to be a Kaiju movie but it wasn't outstanding. Personally, it did not bother me in the slightest. Idris Elba was just epic though. The script felt like it was written in a hurry but it doesn't irk me as movies for me are not all about script writing and plots but the overall picture in the end. Watching this reminded me of my childhood as I watched old Kaiju movies and anime. Pacific Rim paid a great and fun homage to the Japanese culture regarding the mecha and Kaiju genres.
The visual effects were to die for, I was just drooling over everything. The robots' designs were significant and unique and the Kaijus just looked very bad-ass. The fight scenes for me were not hard to follow at all, I can very clearly tell who was bashing on whom, and they didn't feel clunky and choreographed. The 3D was outstanding, just it being in 3D kind of made it for me really. We really don't see movies like Pacific Rim anymore, nowadays everyone would rather see a serious drama filled movie than seeing a plain fun and imaginative one.
The soundtrack was composed by Ramin Djawadi who is known for his work in Iron Man and Game of Thrones. The soundtrack balanced orchestral and electrical elements brilliantly and just gave the movie that little push of epicness. One can't help but feel like he's in a giant robot walking down the street all mighty like when listening to this. I give the soundtrack a 5/5.
The movie did not disappoint me in the slightest, flaws included, as they didn't ruin the movie for me as I knew exactly what I was going to see; a great robot/monster smash 'em up. This was even better than Man of Steel for me. I believe that most people would appreciate this movie more if it had a more serious dialogue but to me it doesn't really add anything extra to a movie in this genre. In the sense of this movie being in the mecha/Kaiju category I would give it a 10/10 but in the sense of a movie all in all I would give it an 9/10.
If you want a real deep sci-fi movie with a Shakespearean dialogue then I would not recommend you to see this movie as you'll probably get bored. However, to put this very bluntly if you're a fan of mecha/Kaiju and anime you'll love this.