I'm not sure whether you mean the alien shots look bad because they had to use primitive CGI? That movie's pretty much all man-in-suit and practical props, wit

I'm not sure whether you mean the alien shots look bad because they had to use primitive CGI? That movie's pretty much all man-in-suit and practical props, with a number of shots using rod puppets on blue screen. Those shots do look bad, but it's because of the bad compositing (not sure if optical compositing or bad, early digital compositing, the blacks and matte lines are horrible). True CGI would have looked and moved worse. There's pretty much one CGI shot in there though, and that's when the alien's head dome crackles under thermal shock in the foundry (looks like CGI crackles comped onto man-in-suit plate, from memory). Haven't watched the "behind the scenes DVD" features in a couple years though. I think it even has Richard Edlund and Tom Woodruff talking about how they were one of the last movies to do most everything the old way at that time. I'd say Alien 3's bigger problem is the development hell it suffered from, as mentioned by others.