The key difference between Ice Age and Ice Age: The Meltdown is really just that everything is melting. Otherwise, it's a lot more of the same, and that is definitely a good thing. The hilarious herd is still together: Manny the mammoth (Ray Romano), Diego the saber-toothed tiger (Denis Leary) and Sid the sloth (John Leguizamo) -- so the good-natured, we-don't-know-why-we're-friends-but-we-are ribbing continues throughout the movie. The CGI is still remarkable; it's almost as though the animators settled on this plotline just so they could play around with a lot of water, and their joy at work only adds to our joy in the theater. And Scrat the saber-toothed squirrel is still trying to get that acorn (spin-off, anyone?).
The Meltdown delights in quick funny scenes interwoven with action, and there are plenty of both. The action is pretty straightforward -- our heroes have to get to the other end of the valley before a glacier breaks, melts and drowns them all. The comedy is provided not just by Scrat and the others, but also by more than one random and entertaining musical number and the addition of some new characters: two possums and Ellie (Queen Latifah), a mammoth raised to believe she's a possum. So there's one other new thing, a romantic subplot, but it fits in nicely with the rest of the movie. The world may be melting and mammoths may be falling in love, but everything else is thankfully staying the same in The Meltdown.
