What I like about this sequel: the writers truly tried something different with the 40 thieves plot. The problem: everything we know about the characters has already been said and shown and there is no surprise at all coming from the characters we already know.
Other problem: everytime there is a problem with some real stakes, let's just call the genie to fix it up...
You want to write something different and bring a new threat and a new villain, that's alright. Just don't solve this by having the same exact characters and the same plot facilitators, it totally undermines what you are trying to achieve.
The animation is also much worse than the first, but it didn't bother me so much.
The songs were good and entertaining and there were some inspired scenes, but I will not remember much of this film. It was the obligatory third one...
Review of Aladdin and the King of Thieves
