The tugging question on everyone's mind when they watch a movie with a '2' after the movie title is almost always how does anyone beat the first one? Well, they could also think of 'Oh my gosh I am gonna drool over him/her again; this time I'll prepare lots of Kleenex' but I doubt that Ben Stiller is remotely drool-worthy. So I'll stick to my earlier thought.
So if you watched the first one, which I assumed you did, let me say it from the start. The second's one bigger. And better.
There you have it. But back to the question of how. Would it be the same museum? Same exhibits? How could the mysterious Egyptian tablet do its magic twice? In number two the cast is thrown (literally) into a more prominent museum, but the central characters remain the same. 8 or 9 central characters are either heavily CGI-ed or costumed up, and the rest is just background noise for these 8 or 9. Of course, do not expect CGI and cinematography of 'Jumanji' or 'Star Trek' proportions.
The movie, of course, centers around Ben Stiller but I was never a fan of his cinematic endeavours. But I guess as long as you're happy and raking in the big bucks; you don't see the need to change. And that's the thing as well; Ben Stiller doesn't up his ante; it's the usual big-eyed, mouth ajar, crazy hair expression you always get with him. Couple with the occasional eyebrow furry and fight with a monkey/cat/small animal of your choice.
Back to the movie; it doesn't lack action or pace and manages to hold your attention well. There were a few laugh-out-loud moments, but for most of the time, the jokes are deep and have historical connotations. Kids would be intrigued by the colours, the familiarity of a museum and the coming of life of statues. It is a family movie after all, and it's good to watch an innocent film once in a while; to take away the dirt of the world, if only for a few moments. Watch it if you enjoyed the first one and wanted something more.
