An interesting experiment in the alien invasion genre, where the aliens roam around in the backdrop against the protagonists' personal drama.
Impressive for a low budget, interesting spin on the genre, decent scriptwriting, and we even get to see some naughty alien action (that's what it was, right?).
Just a couple of details: anyone familiar with Mexican geography will be surprised to see the northern deserts have become the jungle forests of the south (the aliens may have the solution to desertification, it seems) and there seem to be a couple of misplaced Aztec/Mayan pyramids straight across from the US border (!).