I was quite skeptical about this movie. What were they thinking about mixing two completely unlike genres, cowboys, Apaches and aliens together? Well, my mistake. The end result is both a good western and a very credible sci-fi movie. So, out of an apparent weird mix came out an original movie under a plausible story line (Sorry, no spoiler, I will not go into the details of the plot).
I really liked the performance of Daniel Craig, Harrison Ford, and Olivia Wilde. All three main actors have in common to be associated with their roles in previous serial movies or TV series, where they played the lead or a key role. In this movie they managed to deliver a performance quite different from the character we are used to, particularly Harrison Ford and Olivia Wilde. I think this is her first key role other than "House" in which you can appreciate the quality of her acting. I hope she gets more opportunities like this to show us her talent.
As for the special effects, they are quite realistic, and it is notable that the insect-like aliens are not hidden with low lighting like in so many alien movies. The amazing thing is that the SFX are not based completely on computer animations (GCI). The film was shot using good old puppets and animatronics for the close-ups, combined with CGI for the battle scenes. Even some of the alien ships were scale models. My only quibble is that one of the alien features resembles a lot the character Kuato in Total Recall [DVD
] (no spoiler again). My respects to director Jon Favreau, a great combination of old and new technology.