What is different about the Assembly cut of A3? I've never run across it.
The Assembly Cut was made back in the mid 2000's for the Alien Quadrilogy DVD set. It comprises of footage that was filmed but either cut, altered or re-edited differently. Some examples.
The Crash
The EEV crash is handled differently. After we see the EEV crash into the ocean, we cut to Clemons walking by himself on the surface of Fury 161. When he comes across the coast he can see the EEV sticking out of the ocean and when he turns his attention towards the beach, he sees Ripley's body. We than see him rushing back to the prison carrying Ripley (In shots that are resemble the Weyland Yutani entering Fury 161 later) and he tells everyone to help retrieve the EEV. In the original cut, after seeing the EEV crash, we cut to a report being made on a computer screen. Instead of finding Ripley on the beach, she's still in the EEV in her cryotube.
Wreckage and Rape
In the theatrical cut, the prisoners bring in the EEV in through a crane while Murphy's dog encounters a face hugger in the EEV. In the Assembly Cut, the prisoners use Oxen to carry the EEV to shore and into the facility. After the EEV has been examined, one of the Oxen dies and two prisoners bring it into the slaughter room. There they discuss their 'ill' intentions towards Ripley and mention how weird it is that an ox in her prime would just belly up and die. When Murphy checks the crate one more time, he notices the Queen Facehugger dangling on the side, picks it up and asks the other prisoner what it is, but he has already left.
Birth
Turns out the now dead Ox was impregnated by the facehugger and during the funeral of Newt and Hicks, it rips it's way out of the ox's corpse. The scene plays out almost like the dog scene but is a bit easier to sit through since the Ox is dead but the Dog is still very much alive. We also see more of the Alien immediately after it's birth from the ox as it stumbles on it's legs and makes a dash across the slaughter room. Thankfully it's a cgi alien and not a literal dog with an alien costume on.
Our Man Golic
There are more scenes with the prisoners in various scenes. Instead of jumping right into "rumor control", Dillon leads the entire assembly in prayer. Before Golic and two other prisoners enter the tunnels to map the area out with candles, they stumble across a vending machine with cigarettes which Golic gleefully smashes open. Kind of gives you the sense that this area was abandoned hastily and that the prisoners have yet to explore every the complex in it's entirety. Also when Ripley is talking with Bishop, Golic decides to have some food in the cafeteria even though he's covered in blood. This leads to his capture.
Clemens bites it
Clemens' death is handled a bit differently. When the alien makes it's way through the air vent into the room, Golic is seen panicking, but calms down to observe what the alien is about to do. There is also a new shot of the alien readying to head bite clemens instead of just cutting to it like in the theatrical cut. After Ripley makes a dash out of the room, Golic looks at the vent where the alien dragged clemens body into and says "Beautiful...".
The Fire Trap
This is where the Assembly Cut actually starts to add things to the movie that were never dealt with in the theatrical version. Do you remember Romeo? The prisoner who was going to rape Ripley while putting on a pair of goggles(?)? He sort of disappears in the theatrical version and was assumed to have died in the botch attempt in capturing the alien. Well, he shows up during the trap and plays a more integral part. After the fire trap is accidentally set off, the prisoners manage to corner the alien in front of the room they plan to trap it in, but it won't go inside. Romeo decides to get the creatures attention, runs into the room with the alien chasing it and Ripley quickly shuts the hatch trapping Romeo and the alien inside. Dillon and Ripley pause a moment while they hear Romeo scream behind the hatch.
Theatrical Cut: Trap Fails
Assembly Cut: Trap is Successful
Two Escapes
Dillon leads a small celebration with the remaining prisoners while Aaron informs Ripley that despite trapping the alien, the company has sent orders not to terminate the alien. In the infirmary, Morse is assigned to watch over Golic who is still acting a bit crazy. He manages to convince Morse to untie him while Golic immediately knocks Morse out. We than go to the hatch where the alien is captured. Golic wants to see the alien but the prisoners guarding the door tell him no. Golic than kills the guards, opens the door and is promptly killed by the alien. After Morse tells Dillon what happened, we than cut to where the theatrical edition picks up with Dillon looking over the guard that Golic killed (In the theatrical, the guard is just another casualty in the botched attempt to trap the creature). Some extra lines are added where Morse is blamed for letting Golic out.
The Ending
The ending also gets altered a bit. When Bishop comes in to inform Ripley that they can save her, one of the company men explains the procedure. After Aaron whacks Bishop on the head with a wrench, there's an extra shot of Bishop grimacing in pain, bleeding red blood and he shouting to Ripley that he's not a droid. After grimacing a bit more, he shouts at the company camera man "No pictures!". When Ripley is seen falling into the furnace, the Queen Embryo no longer bursts through her chest. This was originally how it was going to end since having the Queen burst out of her moments before she is engulfed takes away the choice that she could have survived this endeavor if she went with Bishop.
There are more bits and pieces scattered about in the Assembly cut that I didn't mention here. If you're going to watch this cut, I would recommend watching it on the ALIEN LEGACY BluRay since when the cut was made for DVD, the producers were forbidden to fix the on-set audio issues. With the BluRay, they were able to bring the original actors back (including Sigourney Weaver) to redub their lines that were almost inaudible due to the activity happening on the set. It's a much more finished product thanks to the ADR and you don't have to read subtitles in order to understand what the characters are saying.
So, does the Assembly Cut make Alien3 a better movie for this Alien fan?
NO. All of the fundamental problems I have with the film are still there in all it's undignified glory. But for a film all on it's own, the Assembly Cut is a better experience. A lot of plot holes that were present in the Theatrical Cut are fixed in this version and it does a better job at telling whatever story the movie makers were left wtih. I find the ox being impregnated to be a better choice because the size makes more sense. Successfully trapping the alien brings back that practical element that the Alien is not an indestructible creature and having the survivors of all people willingly free the darn thing is pretty cool.