In order to have the same lead character as the past three films, Ripley is cloned, along with the alien Queen inside of her when she died in the third film. You can see where this is going, as the aliens proved to be far more than what the scientists can handle. The film ended up not turning out to be too bad and there were a few sequences where it was quite intense. However, the plot felt lacking even though it had showed potential. The aliens weren't too much of a threat and they didn't show up that much, it felt like Ripley was more like the antagonist, as well as some of the other human characters. It introduces more variations of Aliens thanks to the way the Queen was conceived. The mercenaries felt like they were superficial additions to the film, not really gelling in. Needless to say, you expect most of them to die anyway. The ending felt like a letdown and felt improbable that they could have survived what had happened.