If dirt is so hard to find, why are all of the characters so filthy?
Can planes, boats and jet-skis run on plain crude oil? There's no real petrol ever mentioned.
If the world is completely covered with water, what happened to all of the fish? The only form of sea-life that we see is that huge fish-beast thing. And couldn't they eat the meat off it, instead of having to share the eye?
If The Mariner is mutating into a sea creature, and can breathe underwater, why does he have that nifty diving bubble? Don't tell me he was expecting company.
How far ahead in the future are we anyway? Hundreds or maybe thousands of years? Do you know how long tankers like that can stay at sea? Twenty or thirty years at the most. That's a rather short time for everyone to forget about dry land.
The bad guys have many cans of Smeat laying about. Why won't they eat it (besides the obvious, I mean)?
At one point, the mariner trades a handful of dirt for water and a potted plant that has more dirt in it than he originally traded.
Right before the Smokers show up, you can see land on the left hand side of the screen.
There isn't enough water in the icecaps to submerge the Earth. Even if there was, the salt water would be diluted enough to drink.
He is screaming along on a port tack (sailing term). The camera pans out, and he is now on a starboard tack.
When they leave the land where Anola lived, they come upon a trader. The trader offers him paper to trade for 30 minutes with the woman. When his ship is destroyed and he recovers his valuables, he finds some National Geographic magazines. If he had so many magazines, why did he want the few pieces of paper?