This point has been well and truly hammered in all the marketing for this movie, which means a big chunk of the plot elements are given away already (to anybody who has ever seen Jumanji). In fact it is a sort of sequel, in that it uses the same plot device of a board game that changes reality for the duration of the game.
All the action takes place in and around the house as it moves through space, being gradually demolished in spectacular and messy ways, and there are a couple of good twists to the plot. Its main failing from my point of view is that it dwells too much on a particular group of aliens (The Zorgon), where Jumanji moved forward from one threat to another to another and they all accumulated to the finale. The pace is also a lot slower than Jumanji for a lot of the movie, so they end up encountering a lot less stuff, which makes the movie seem shorter when in fact it is 9 minutes longer (113 minutes).
An amusing and fun adventure movie that earns its PG rating from the swearing by the two boys (10 & 6 3/4) rather than any real violence. In fact I do wonder why they added the swearing given the fairly weak response of the father to their use.
I give it a 7 out of 10. A fun movie you can take pre-teen kids to without going brain dead.
(Hint: Look for the bicycle in the outside scenes :)