Okay but seriously this has now infected my mind and I need to make something about this before I lose these thoughts.
This is my hypothetical plot following these songs here we go
1. Another Day, Another Dollar. A big, explosive opening number starring all the science team members, first singing about working at Black Mesa before then switching to singing about Gordon, becoming like a Greek Chorus foreshadowing what is about to happen.
2. Passport? Benrey repeatedly tries to stop Gordon from going through the facility to get his passport. Gordon and Benrey run into Bubby, who joins in on Benrey’s whole passport crusade (and simultaneously melodically foreshadowing Idiot/Friend as well.) The song ends seemingly with Gordon closing a door on Benrey, only for the song to end with Gordon’s massive f-bomb getting cut off.
3. Resonance Cascade. Pretty self-explanatory. A song about the resonance cascade starting. Ends with Gordon getting violently zapped.
4. You Fucked It Up. A passive-aggressive song starring Bubby sniping at Gordon repeatedly as the Science Team regroups to make it through the rest of the Cascade unharmed.
5. It’s All Up To Code! (The OSHA Song.) As the Science Team traverses the dangerously unstable Black Mesa, Tommy sings about how it’s all perfectly safe and up to good. He also sings about Sunkist the Dog and his parents he never knew. This ends with Benrey seemingly dying from being crushed by a door that Tommy says is safe.
6. Black Mesa Horror Show. The military is here and everyone is dying. The Science Team sings about how fucked up the whole situation is while the Black Mesa Announcer joins (Maybe a bit of You Fucked It Up thrown in why not,) and then the mood suddenly shifts with Benrey coming back from the dead and harassing Gordon for his passport.
7. If This Hadn’t Happened. Moving this up here mostly because of Dr. Coomer. The Science Team sings about what they would be doing at that moment if the Resonance Cascade didn’t happen, and it takes an eerie turn when Dr. Coomer tries to figure out a way to leave and finds there isn’t a world outside of Black Mesa.
8. Idiot/Friend (Step Inside Gordon.) Benrey convinces Bubby to help him get rid of Gordon Freeman due to him rejecting his advances, and they successfully trick Gordon into getting his arm cut off by some soldiers. The Science Team abandons Gordon to die.
Act 2
9. Betrayal. Gordon awakens to consciousness, sees his gaping wound, and sings about his feelings of abandonment and betrayal. Thankfully, Tommy comes back and promises Gordon he would never abandon him.
10. There Is a World In Your Dreams. Coomer’s big number, and technically has a choir of Coomers. Dr. Coomer sings about the world, about how there is no world outside of Black Mesa but one remains in Gordon’s head as he attempts to hijack his body. Ends anti-climatically with the last Dr. Coomer joining back up with Gordon Freeman and Tommy.
11. Tube Song. Bubby, trapped in his birth tube, laments his mistakes to the tune of You’ve Fucked It Up. He wonders if, the whole, he was the one to “fuck it up.” Gordon and the gang arrives and Bubby is freed.
12. The Neo Science Team. The Neo Science Team meet Darnold, and with the help of cybernetic enhancements, the Science Team’s dour morale is fully restored. They are back in action. Before they fully leave, though, the G-Man arrives and appeals to Gordon to keep his “progeny” safe, reprising the OSHA song to do so.
13. Hostage Situation. As the Science Team travels to the Lambda Complex, they meet the last US Military Soldier: Forzen, having kidnapped Sunkist hostage. Reprises Black Mesa Horror Show and the OSHA song before Forzen literally fades-out. Ends with the gang traveling to Xen with a final warning from the G-Man.
14. Passport Guardian (You Made Me Be Bad.) Benrey’s big villain number. It’s a series of complete word salad non-sequiturs about how Gordon made him bad before transitioning to a big battle that ends with the Science Team, on the pit of despair, having Gordon go back in time to delete his passport. Reprises numerous songs from before.
15. Back to Black Mesa. Gordon hides from Benrey as he tries to find his passport.
“I set you Free, man,
so I could suck your feet, man.”
Gordon deletes his passport and gradually brings back Dr. Coomer’s memories, as indicated by The World Inside Your Dreams. In one last battle, they defeat Benrey and beat the game.
16. Birthday Party/You Beat The Game. The Birthday Party is simply that: Tommy’s Birthday Party as arranged by the G-Man, which leads into a final number congratulating Gordon on beating the game from all the members of it. It ends, however, with a somber rendition of The World Inside Your Dreams, where Dr. Coomer appeals to Gordon to bring them with him on his next adventures.
Had to get this out. Thank you much to @the-meme-monarch for the original concept holy shit.