'The Adventures of Shark-Boy and Lava Girl' is a terrible movie and there is no other way to put it.

Story

Max is a lonely child who lives in Austin Texas with his parents. He creates an imaginary world called Planet Drool, where all his dreams come true. He also creates two characters called Shark-Boy who as the name suggests is half-shark, half-boy and Lava Girl who can produce fire and lava. One day, they appear to him in the real world and bring him to Planet Drool, and help them save it from Mr Electric, the dreamworld's now-corrupt electrician.

The story is as ridiculous as it sounds, given that this is a kids movie. It's pretty simple which ideally makes it easy to follow, but all the other elements surrounding the story make it hard to concentrate on the actual story. While writing this post, I found out that a lof the concepts were thought of by Robert Rodriguez's children and that makes a lot of sense because the story is absurd.

Acting 

This movie does have a decent cast, Taylor Lautner, David Arquette, Kristin Davis, Sasha Pieterse and George Lopez but there isn't anything positive to say about their performances. I don't fault the acting in too much because the actors work with what they're given, which isn't much.

There's an evident lack of harmony when you look at the performances. Some of the actors are putting in too much effort while others aren't putting in enough. That makes the whole movie feel inconsistent.
The actors also lack chemistry. They never feel like they would interact with each other if it wasn't a requirement.

The acting isn't necessarily bad but that doesn't make it good, overall the whole thing feels unnatural, making the movie awkward to watch. Overall it's stale and lacks any kind of substance.

Writing/Direction 

The writing is one of the weakest aspects of the movie, it's cringy and lacks any real substacne. A lot of the dialogue sounds like it was written by someone who knew nothing about kids, a fact I found surprising considering Robert Rodriguez had kids when he made this movie.

There is no solid direction in this movie, there is no coherent flow, the movie jumps from scene to scene without providing any type of transition. This affects the pacing of the movie. This movie has a runtime of 89 minutes and even though it doesn't drag I wasn't engaged at all thoughout.

Unlike a lot of other kids movies, this one lacks heart and ends up feeling very hollow.

CGI/Set Design 

This movie is a visual mess. This is a prime example of working beyond your means, the budget isn't able to sustain the vision and it shows. The filmmakers were trying to make a film that wouldn't have worked with the visual effects being used in 2005. If the movie was made today, it would have looked much better because of the advanced CGI that we have now.

However, that doesn't excuse the terrible set design in the scenes set in the "real world". This movie is visually crowded. Every scene is filled with so many props that you lose focus on what you're supposed to be looking at.

Score/Soundtrack

The score is pretty much non-existent and what I noted is nothing spectacular, it was on par with the quality of the film as a whole.

Taylor Lautner does have a song (with a dance break) in the middle of the movie. And it's as ridiculous as you think it is. There is a narrative reason but it's distracting and to remember why it's in the movie

For your viewing pleasure.

Overall Thoughts

I'm used to suspending my disbelief when it comes to kids movies but it was really hard to that here. The whole premise of this movie sounds too far-fetched for you to engage with. I know what you're thinking "This is a kids movie, you're not meant to take it seriously" and I agree, however, this is a movie and I watched it the way I would any other movie. This movie is objectively bad. 

You have a movie like Spy Kids, made by the same director that have substance, a good (and clearly discernible) message and is also a generally good movie. This one, on the other hand, lacks everything that movie has.

The whole movie is cringy and borderline unwatchable. It's aged terribly, I lost interest within the first 30 minutes because of the terrible dialogue, distracting CGI and ridiculous premise.