Unfortunately I'm not allowed to share the script, but I can post differences between early Roberts' draft and the final movie. As far as I remember:
- Claire arrived to Racoon City just to get her brother out of the dying town, she didn't show him Ben Bertolucci tape and didn't tell him any conspiracy theories, she doesn't know what's going on in Racoon outside of all the weird and scary stuff that she saw when she arrived or when she escaped The Raccoon City Orphanage when she was a kid. She also didn't know Ben Bertolucci personally, Ben was a TV reporter in Racoon who claimed that Umbrella poisoned water in the city.
- Truck driver tried to sexually assault Clarie, but she quickly "disarmed" him and it didn't go any further. Part of the scene is actually in the film.
- Leon had more character development and kind of a character arc. There was an extra scene when Leon woke up in hangover, his father called him and expressed his disappointment in him after that accident with Leon's partner and that he hopes Leon won't embarass him even more on a new job. Leon was really embarassed he let down his big name father as he watched their family photo from Leon's police academy graduation. He was still kind of comedy relief character, but I thought it worked in the context of the story, he had an underdog hero's journey arc. He's incompetent, but gets better and in the end saves the day by killing mutated Birkin and I guess making his father proud. There was an emphasis on this arc that I felt was missing in the final film.
- Dialogues were noticeably better with a lot less exposition and character names dumps.
- Raccoon felt more developed in the script and there was no exposition text, with bigger emphasis on its current status.
- Rebecca Chambers and a bunch of other characters had cameos in a caffee instead of Wesker and Jill. One of the cops (not Wesker) tried to make fun of Leon because of his backstory with shooting his partner, but Rebecca calmed her teammate down and was really nice to Leon. Wesker, Jill and Chris actually made fun of Leon in the police station by putting different things on him while he was peacefully sleeping after hangover. They had some extra interractions where Chris and Jill were foolling around the police station while Wesker watched them (it's implied that Wesker has feelings for Jill, just like Chris, but they are just close friends since school)
- There was Barry Burton instead of Richard Aiken and he played the same role, so it was more a character name change.
- There was an extra scene with Ada Wong. People complained that Wesker was dumb in the final film and was manipulated by phone messages, but in the script he secretely met Ada in the police station behind his friends' backs, to discuss what he has to do in Spencer Mansion, right before they board the chopper to fly there.
- Jill was a bit less agressive and rock-n-roll, probably closer to games.
- During chief Irons' briefing in the police station he reported that Chambers' team didn't come back after they went to check reports of animal attack near the Spencer Mansion and he also got audio messages with screams and shooting. There was a funny scene where Barry, after hearing those messages and a long pause, assumed it was a bear and everyone in the room rolled their eyes and looked at him like he's an idiot.
- Chief Irons was such a coward he was ready to leave his family in Raccoon and tried to escape the city without them as his wife tried to call him to find out what's going on in the city, even though Irons felt guilt about that. There was a very similar scene to Resident Evil: Apocalypse where large crowds of people and cars gathered near the walls with Umbrella's mercenaries. Irons tried to use his status to escape, but mercenaries wouldn't let him. Then mercenaries opened fire at people when they saw first infected folks in those crowds and Irons had to drive back to police station to find some other way to escape. It was probably cut because of budget constraints.
- Wesker's betrayal was better written. After Jill saved Wesker from the fallen chopper, a bunch of zomies started moving towards them and Wesker grabbed Jill's hand and took her to the room with a piano. Then he opened the tunnel to the lab and told her about his secret connections and real plans in the mansion (steal Birkin's documents, earn a lot of money and escape the city using the underground train). Jill told him that she actually knew about his secret meetings and the same people tried to make the same deal with her, but she would never agree to betray her friends, so he should just forget about this nonsense and come with her to save Chris. Wesker thinks that Chris is probably dead and that risk of coming back is not worth it. Jill doesn't believe what she hears and pulls Wesker to come with her (come to light in a symbolic way). He hesitates for a second, lets her pull him, but then says no and leaves, entering the tunnel to the lab, betraying his friends to save his ass. Jill on the hand runs to find Chris, she saves him from zombies and they both fight their way to the tunnel. In the contrasting moment, wounded Jill asks Chris to leave her to save himself, but he point-blank refuses to leave her.
- Wesker reluctantly threatened Birkin and his family to give him documents and was really surprised he took his wife and daughter here. Birkin ouright refuses to give the work of his life and opens fire at Wesker. Wesker returns fire and mortally wounds Birkin. Annett Birkin calms her dying husband, then suddenly grabs husband's pistol and wounds Wekser. Wesker docks to cover and blindly shoots back, killing Annett. Wesker is shocked by what he just did, he never killed anyone before. He really regrets it, calls Birkin a madman because forced him to do this and screams to Sherry that he didn't want to kill her parents. But there's no turning back.
- Wesker was "killed" by mutated Birkin, not Jill. Chris and Jill came to Birkin's lab a bit later and found Wesker's body.
- Birkin was a bit more likable and scenes with his family life were different and a bit longer.
- Birkin had no personal connection to Chris at all, he took no part in his education/growing up and they probably hadn't seen each other since orphanage.
- Lisa Trevor showed up in the final battle to help our heroes and attacked fully mutated Birkin on the train. She jumped him like raptors vs T-Rex in Jurassic Park, but after some fight Birkin killed her.
- After our heroes escaped Raccoon, they had a conversation that Umbrella must be stopped and the world must find out what really happened in Racoon. Leon sighs and says he needs a drink. That was actually the only "save the world" dialogue, all characters' motivations throught the script were personal.
- Wesker's ressurection was part of the ending and not post-credit scene, but it's word to word the same as in the script.
This all sounds so much better. It addresses the problems I had with the script.