Do not over-analyze this film !

Rating: 6/10 (4 August 2002)

***WARNING : DO NOT READ FURTHER IF YOU DON'T WANT SPOILERS****
This film is not one that is meant to hold up to extreme analysis regarding the aliens' logic. It is a film that is based upon issues that go much deeper than alien invasion. It is a film that deals with a person's faith, and how we may indeed be given "signs" from a Higher Power everyday of our life without realizing it.
Because of that, it really bothers me when I read people criticizing the film for certain aspects. Some of the such criticisms included naming the aliens' vulnerability to water as "silly" - because they are invading "a planet that is 2/3 covered by water.". Another recurring criticism was regarding what the viewer felt was a "cheap looking special effect" in the portrayal of the aliens.
To me, these criticisms only show that the viewer was viewing the movie in a very shallow way. First of all, the aliens' vulnerability to water. Just for the sake of addressing this question, let me say that one could make a case that the alien invasion depicting in this film was only the BEGINNING of the invasion. This is actually hinted at by the army recruiter who says there have been reports of "people in shadows", and that those are reconnaissance tactics to just see the "level of danger" in an invasion. In other words, we are only seeing the very FIRST aliens to ever come to this planet. These are the aliens that come to an alien planet to see if it is safe for the rest of the aliens ! Sure, they might have a vulnerability to a fluid which takes up 2/3 of our planet's surface - but can they still use the remainder 1/3 of the planet ? So we are seeing that first "wave" of aliens - the "reconnaissance" mission.
Another way of addressing this criticism is to address it in the same manner as the "alien looked cheap" criticism. My response to this is "so what ?". Is that what you REALLY came to see this film for ?
In all fairness, the water issue goes much deeper than simply the aliens' vulnerability to it. It goes into the true underlying theme of the film : faith. The water here is used an instrument to illustrate some of the religious undertones of the film.
As for the film itself, M. Night Shyamalan did a brilliant job in keeping me tense throughout the film with his quick glimpses of an alien leg disappearing behind a corn stalk, a quick shot of a shadow figure on top of a barn, or quickly moving shadows behind a boarded up door. The whole time I was wondering what exactly was going to happen. Would there actually be an all-out invasion ? Would we only see hints of the aliens ?

Shyamalan's answer to this was perfect. That is because he managed to bring together the true theme of the film (faith), with the alien invasion. Also, by only interacting with one singular alien, Shyamalan also seems to be further expressing the fact that this is only the BEGINNING of the invasion. In other words, the viewer shouldn't necessarily consider this as though the aliens' are now "defeated". This is only round one of the invasion....but until round two takes place, keep the faith.
Don't misinterpret that as a call for a sequel because there should NEVER be a sequel to this movie. It ended perfectly.