Based on Disneyland's theme park ride where a small riverboat takes a group of travelers through a jungle filled with dangerous animals and reptiles but with a supernatural element.
 
No review.  Just a quote from the movie.
 
[on a standard riverboat tour]
Frank Wolff: Ladies and gentlemen, the moment you've all been waiting for.
[Frank surreptitiously triggers a device that flows water over the boat and into the river]
Frank Wolff: The backside of water!
Boat Tourist: It looks just like the frontside.
Frank Wolff: It's the eighth wonder of the world.
 
Nuff said.
 
FUN FACT:  Many of the puns Frank uses are taken directly from the Disney Parks attraction on which the ride is based. These "so bad they're good" jokes are one of the reasons why Jungle Cruise skippers are so important to the ride experience.  Moreover, there are several elements from the park attraction featured in the trailer.  The most notable is the "back side of water" gag that most of the cast members use during the attraction.