okay guys here's the promised masterpost on Iron Lung lore for your BloodyMary fanfiction: (cutoff for spoilers)
at the end of the movie, Simon has radiation poisoning (from the x-ray camera; levels that should be fatal), alcohol poisoning (he drank isopropyl alcohol), possibly one or more concussions from blacking out and bouncing around the ship multiple times, lost an arm, and is in the process of mutating due to exposure to the blood in the SM-13 (has likely also lost one of his eyes as it looks clouded over before it becomes swollen to the point that you can no longer see it, half of his face looks boiled along with his body, and eel-like fangs are sprouting out of his cheeks)
each photo Simon takes uses 7,800 millisieverts of radiation; one whole body dose of radiation over 700 mSv can cause Acute Radiation Poisoning
the movie ends with Simon fusing with the tree seed he was carrying; the tree essentially explodes out of the SM-13 and kills Ellie (the eel/monster) (you can see this in a BTS CGI rendering--it's also possible to see it in the film, but the scene is very dark); Simon turning into the Blood Tree (as the Wiki calls it) can also be seen as a callback to The Father's quote earlier in the film: "The last tree WILL live again! When the Last Son of Eden joins the Grove, there will be a thousand trees!" which would make Simon the Last Son of Eden
Elli, the eel/the monster, is a mutated conglomerate of all the people in the SM-8; she speaks with the voice of the SM-8 research lead, who had begun obsessively drinking the blood from the ocean, which is likely what led to the SM-8 crew mutating into Elli, similarly to how it is mutating Simon
the "ignorant god" that Elli refers to is the Eye that Simon sees--it is implied that the Eye is peering into their universe from Its universe (which is red and bloody) and either a) reshaped their world either in Its world's image (the Red Void) or b) reshaped the world according to the first thing it saw--the inside of a person or animal (which is filled with blood)
in the video game, the clearest interpretation of the Quiet Rapture is that it was the biblical apocalypse from the book of Revalation and the reason that all the space stations remained is because they weren't on any of the planets (however, these implications are not present on the same level in the movie--rather, the implications are what the above bullet point says)
Simon has seen the ghostlight of stars; seeing a live star would be new for him, but it would not be his first time seeing a sky that isn't empty
Simon grew up on Eden, (in the game it is the largest remaining spacestation that was originally a Mars colony), which is largely implied to be a cult--they have the Last Tree, which is revered, they are led by a man called The Father, they refer to themselves as Children/Brothers of Eden, and they have tattoos on their necks with the symbol of Eden (Simon's was burnt off by the C.O.I); each of them carry a pendant with a leaf from the Last Tree
it is implied that Eden attacked Filament Station to get bodies to use as compost for the Last Tree, however instead it blew up and killed 62 people
the Light is what triggers Simon's vision of the Eye and the Red Void in which It lives--Elli knows of this connections and seeks to hoard it for herself, only wanting those she approves of (like Simon, initially) to have access to it
Simon is implied to be less religious/cultish than others in Eden, such as the previous occupant of the SM-13 (he chooses to follow the orders of the C.O.I over because he explicitly wants to live, rather than wanting to find his freedom "beyond the Veil"
Simon's sub most likely refilled its oxygen bars through the blood that seeped in, as blood contains oxygen
Simon started hearing Elli after blood from the ocean leaked into the SM-13 and got on his face
Elli refers to the SM-13 as being alive (this would be due to exposure to the blood ocean), and her claim seems to be confirmed by his arm becoming stuck to the ship (before it rips off)
for further research, here are video essays about Iron Lung that I have watched and reccommend:
the hallucination Simon had of the mutated person in the SM-13 may have been of himself
the only parent Simon mentions in the movie is his mother, meaning he likely a) didn't have a good relationship with his father or b) didn't know who his father was (dead or alive); it is also heavily implied that his mother is dead and there are no other clear mentions of him having other living family members
Hail Mary and Iron Lung: How We Face the End Times
Solving Iron Lung: The Entire Movie and Lore Explained
Iron Lung: Complete Lore and Story Breakdown
Everything We Know About the Iron Lung Movie
I haven't watched it yet, but there is also a documentary on the making of Iron Lung! You can find it here. It may have some things I missed--if so, I'll reblog this with addendums.
