Liked: Sigourney Weaver, who was at the beginning of this sort of movies starring in "Alien", was offered to play blue monster in this movie in 2009 - liked the fact itself. Liked main heroine - her facial expressions and gestures are truly alive (beautiful and wild - Pocahontas of SF movie as my friend said). Also monsters appearing in this film are something - each of them is mixture of animal, bird and exotic insect in one...
Didn't like: but if you imagine it all played by old clay monsters of 80s, you`ll find that the plot itself is very typical, very-very typical for Hollywood movies (I think TITANIC by the same director James Cameron made viewers feel more strong feelings and made think more, than his new work).
Nevertheless, remember - don`t kill fluorescent insects - they may be sacred spirits!
