Before I begin, this writer has great potential. Very descriptive scenes and a good handle on story structure made this an easy read. That being said, here are some of the things that could be improved upon.
1. Opening scene. The interchange between Damien and Alex doesn't seem to fit with the rest of the story. Aside from giving further fuel for Tiffany to dump Damien, and providing a way for Damien to become intoxicated (making it easier for his captors), it doesn't set up the rest of the script. Perhaps you could start with the flashback of Tiffany and Damien at the bar, and then cut to him drinking alone. Then you could use their breakup fight as another memory. Not sure if that helps, but it's an idea.
2. Action. There seems to be a lot of action description, which makes this read more like a book. You can't really SHOW what a character is smelling or thinking unless there is some kind of action or dialogue to accompany it. Don't get me wrong, these descriptions are super helpful for the reader, as they set up the scene really well, but I'm not sure there is enough compelling dialogue.
3. Character development. As a reader, I didn't feel connected to Damien the way the audience should empathize with a main character. This could be to a lack of backstory, but he needs to be more likable somehow. Also, there needs to be a definite change in his character over the course of the screenplay. He starts out much the same way that he ends. Some questions to consider might be: what are his stakes? (aside from losing his life, there isn't a real reason we want him to win) what does he want/need? why is Jack trying to help him only to kill him?
Overall, I thought this script was interesting and well structured. I especially liked all the cutaways to Marcus and his escape attempt. The flashbacks pulls the audience in more and helps establish some of the character backstory. However, because of the things mentioned earlier, this could still use a little work. I would focus on some kind of theme or "lesson to be learned" to tie the whole thing together. Again, good dialogue is crucial, so keep working to spice things up (without resorting to just swearing...gets a little repetitive) Thanks and good luck!
