The deception by the aliens on humans is one of the interesting things about the movie, and the other being the flirting between the Pierce Brosnan and the Sarah Jessica Parker characters. The latter is actually quite charming, especially as a dog. Other interesting characters are the forgetful lady and the disguised alien.
The movie is overall entertaining, but has just too much violence... the attacks are prolonged. The sub-plot about the former boxer is horrible, complete with bad acting and uninteresting characters (boxer, wife, kids) and looks like it's from some shitty B-movie. The whole thing is also pointless.