Maybe they didn't realise water hurt them because they live on a planet without any

Rating: 9/10 (15 November 2012)

I've felt obliged to register an account just so I can answer some of the objections being raised by the negative reviews for this film.
Foremost among them is the question that "why does a super advanced alien race which has a weakness to water chose to invade one of the only planets in the universe with liquid water present?" Most asking this question are presenting themselves as paradigm's of logic.
But they state the answer to their own question within the question. Most planets in the universe do not have liquid water present. Therefore, it is possible, and even probable, that the invading aliens are from one such planet. It is therefore more than possible that they did not realise they had this vulnerability. I think humans would be caught similarly unaware if we invaded a planet an found we had a deadly vulnerability to the gaseous form of gold, for example (ignoring temperature as an issue.)
Other criticisms are why such athletic aliens cannot brake into a boarded up house. However, they do brake into the house. Really quickly. They just avoid doing it via smashing through wood and instead find an easier way in. The latter option, to me, indicates a higher level of intelligence.
I could go on, but I'm just going to say that you could either a) suspend your disbelief or b) stop trying to be the biggest intellects on the internetz. The film is wonderfully crafted, has a great score, the acting is first rate, and the culmination of several different plot threads into a singular tense ending is great. There is lots of things to like about this film, and seemingly a few to dislike if you really try hard enough.
But don't try that, just enjoy it for what it is.