What a horrible mess this movie is. The premise: somewhere in some topsy-turvy universe is a pair of planets literally within spitting distance of each other. Here are the three rules:
1. All matter is pulled by the gravity of the world that it comes from, and not the other.
2. An object’s weight can be offset using matter from the opposite world (inverse matter).
3. After a few hours of contact, matter in contact with inverse matter burns.
Okay. I can deal with stuff like that … if it sticks to the rules. But this movie doesn’t! For instance, one world is rich and the other one is poor. The rich one (Up) exploits the poor one (Down) for its oil. Okay, so you pump the oil to Up … and in a few hours it burns, right? No time to refine it. Up’s atmosphere would be very ugly. There are literally dozens of instances where this rule is ignored; it is used only when needed to move the plot along. It’s a story of two star-crossed lovers. (If it were Romeo and Juliet, Romeo would be standing on the bottom of the balcony and the two would be leaning over to look at each other.) They would have to be very careful not to hold onto each other too long. Talk about red hot loving!
When they have committed a fundamental error like that, it’s impossible for me to ignore other little things, like the shape of the planets. The intro shows them to be spheres. If they are, then only at this one point would it be easy to travel between the two. If they are not, what are they? Infinite planes? Discs? Either way, it would be damn dark unless the sun stayed in one place of eternal sunrise. But it doesn’t. The sun comes up over Up, and that’s that. Very, very stupid.
I could go on and on, but that’s enough time wasted on this dumb movie. And it’s too damn bad, because visually it is a delight to look at, both the long vistas of scenery and the interiors with people on the floor and the ceiling. Which pisses me off even more, because they took such an intriguing premise and totally fucked it up. Or down, depending on your point of view.