I love monster movies as much as the next guy. Predator, Alien, The Thing, The Host, are all great monster movies about a creature from another world (or from industrial sewage) that comes into ours and sends everybody running. Now really, this is what the original Jurassic Park was. A creature from another world (in this movie the world being the past) enters ours and things go horribly wrong; people run and scream, and if you're Samuel L. Jackson, when things get crazy all that's left of you is an arm to greet the pretty blonde who's knocking at your door. So I can't argue that this movie is somehow beneath the original because it is simply a monster movie, because the first film was too, the difference is in the execution.
The cast of this film does the best it can with the material it's been given. Chris Pratt tries to make his macho raptor wrangler relatable, but he's really just a cartoon caricature of Indiana Jones. Bryce Dallas-Howard has the unfortunate role of the Jurassic World manager/ love interest of Chris Pratt. She spends the entire second half of the movie running from dinosaurs in high heels (she even manages to outrun a T-rex in them), and finding herself caught in slow motion T&A scenes that look like something they found on the cutting room floor of a Transformers movie. The obligatory children characters aren't bad, they're not as good as the children in the original film, but we can hardly fault them for that; none of the character equivalents in this film are. There's a ridiculous subplot with Vincent D'Onofrio's character and B.D Wong (he was in the original film. He's the scientist who says, "All the dinaosaurs in Jurassic Park are female") where the two of them plan to use raptors as weapons for the military.
Another huge problem is the villain of this movie. The genetically bred Indominus rex. So, in this movie the public's grown tired of regular old dinasours, so the owner of Jurassic Park (John Hammond is dead, and it's been handed down to one of his associates) has cleared for the creation of something sexier: more teeth, bigger claws, ext. This thing turns out to be a huge mistake, escapes, and goes on a killing spree throughout the park. Doesn't sound too terrible, right? The problem is in the quality of the execution. This is where the monster movie tropes that Jurassic Park managed to make fresh by presenting the dinosaurs as animals merely doing what carnivorous animals do (hunting for food) are thrown out the window in favor of something that's supposed to be scarier, but actually feels sillier in the context of the film: the dinosaur is hunting for fun. This worked in The Ghost in The Darkness (a film about man eating lions), it does not work here. It just adds to the campiness. In this movie the Indominus rex is the bad guy, and the "normal" dinosaurs are the good guys. This includes Chris Pratt's gang of trained raptors, as well as the T. rex and the new water dinosaur, the Mosasaurus who all avoid killing the good characters and only seem to want to attack the evil Indominous rex or the other evil characters of the film.
So on top of all those issues, the dinosaurs and the CGI backgrounds look especially phony in this movie. Everything is all too shiny, and looks especially fake when contrasted with the scenes that do take place in real vegetation with actual humans. However, when the CGI dinosaurs are masked by the darkness of night, they almost look real. Unfortunately most of the film takes place in the day.
Over all, I have seen worse movies. It's not as bad as some other summer blockbuster sequels, and if viewed as an ironic comedy, it might even be a little fun to watch with friends. However, In most other circumstances it's a film you can definitely skip.