"First of all, it is difficult to empathize with (or care about) any of the characters in this film. And there is very little in the way of character development, that might help this problem. I've heard that this film was heavily cut before its theatrical release, and that there is a much longer director's cut, which is ultimately more satisfying in this respect. I wish Fox had used it here. Another problem with Alien 3 is its poorly conceived and written script. To start off with, we're asked to accept the idea that the alien queen managed to lay a few eggs unnoticed in the scant minutes she was on board the Sulaco. Then we're asked to believe that a single face hugger could cause enough damage to require evacuating the crew in an EEV, and then we're asked to believe that the EEV just happened to eject near a populated (albeit sparsely) planet. To make matters worse, all of the survivors of the previous film are immediately killed off (problems with budget or contract negotiations perhaps?), including Ripley's surrogate daughter Newt. Which leads to the script's other major problem - it's just a major downer. After the sheer horror of the first film, and particularly coming off of the edge-of-your-seat thrills of Aliens, this film seemed far too subdued and somewhat less than frightening. It just wasn't at all what I was expecting. Which is not to say that the film doesn't have some merits. I did find the quasi-religious undertones of Fury's inhabitants compelling. And the concept of the alien creature taking on some of the physical characteristics of its host (in this case a dog) was intriguing. But again, the film stumbles over another major shortcoming, which is that the creature effects are just, well... bad. More often than not, the creature effects were accomplished by using a marionette-type puppet that was shot in front of a blue screen, and optically added to each shot with the actors. In other cases, its just a mechanical prop... and it shows. The first time we ever see the creature (in chapter 9), it just looks silly. The best thing about the creatures in the first two films, was that we barely saw them. They were far more frightening. Here we're seeing way too much."
January 1, 1970
https://en.wikiquote.org/wiki/Alien_3