I wasn't a huge fan of the "everyone died" ending either
Doesn't matter at all to the puzzle, and I do like the idea that the innocent characters are solving the puzzle along with the players of the game, and so they figure it out when the players do...
2. Is this story based on anything in particular? What were "the documents"?
Nope, and there was really no backstory. I ran this game for the puzzle part, not so much for the flavor; I'm definitely a function over form person (read any of my modded games and prepare to cringe). The documents were purely a plot device, I had no idea what they were-- although it wouldn't have been hard to come up with something a corrupt executive was covering up, that wasn't really the point of the puzzle
3. How did you go about creating this? I would probably fail miserably, which is why I decided instead to do my puzzle based on just liars and truth-tellers instead of a story.
I did it all in one weekend, with no internet access no less, so let's see how well I can recall.
I was brainstorming possible flavors that wouldn't have been a copy of Segaco's, not that that would have been bad (and Segaco's flavor is the most cliche murder-mystery story imaginable anyway
) but I just wanted something different. I came up with this one, and started planning out the characters and the setting.
After I had determined all the characters and the map, I rolled dice to choose the murderers. (Can't say it was REALLY random since I would have rerolled if I hadn't liked it, but I did like the scumteam, if you will, so I kept it.)
Then I just came up with plot devices. Pretty soon through the story I had decided both who would survive to the end and who their likely partners would be-- hence why I was completely unsurprised that you tried Alpha/Alder and Tom/Miles before getting the right answer-- and I geared a lot of the situations around making those teams all seem fairly possible. I erred on the side of making them seem TOO possible, which is why I had to clarify so much in red. I do think it was better, because otherwise it probably would have been a little discussion, and then the right answer as the only logical conclusion.
I borrowed and modified some plot devices-- the question of ammo in the guns, tracking who has what keys to what rooms, hiding, the loud sound from knocking over furniture, and sliding the key under the door (which was brought up in the first puzzle but ruled to be impossible) -- and I invented some of my own-- the documents, the window at the bottom of the door, the elevator, and the sirens (needless to say, these are all dumb flavor-wise but they make the puzzle more interesting
).
Then I just read over it and tried to see where the evidence to disprove the incorrect teams would be. For Alpha/Alder I had intended the guns to be the issue but I got outsmarted by not realizing that Alpha could have lied about his gun's size and switched with Ren, and for Tom/Miles I think Ruby's and Catherine's deaths were both difficult to explain.
If you do want to try your hand at something like this, I'd say at least make a rough draft and see how it comes out. It's fine if the flavor is cringey, it's fine if there's initially not enough information or you didn't think of everything (God knows I didn't)... really the only important thing is that you don't contradict yourself or accidentally rule out the correct answer. Given how much you seem to enjoy logic puzzles, I'd suggest you give it a shot