For some reason, my computer is trying to treat the pages as 3 A4. When I tried to convert over to spread and see how the system handled it for print, it left a lot of extra space. At first, I thought maybe they were A4 pages instead of A5, but when I did the pixel rate to dpi conversions, it was within the A5 size range with only a few pixels short on the long sides. I have no idea what is going on there, but since the system says it is indeed A5, I have to assume there's just some small issue I don't understand.
I do a quick scan of the document and see it's largely a dungeon with the first page dedicated to system-elements. There's a map referenced with a functional link. I can only assume it was due to issues with the reprinting of someone else's maps. I'll be honest here, I would have been happier with a map included. Especially considering you only used 3 of your 4 pages. Even if the map 'quality' was a little lower, having it with the document to directly reference back to instead of linking to a second page is more in keeping with my preferences. If I was printing this out, that map wouldn't automatically get included on the 2 sides after all.
System neutral conversions and notes are comprehensive. I doubt most GMs would have any issues finding their way around the information. The down side is it does make the pages with information feel cluttered. I found myself referencing back to page 1 a lot just to be sure I was understanding correctly. Was this one bold underline italic or bold underline? The little arrow was paths right? Seems like a path but let me double check. You get the idea. Based on the fact this is referenced as part of a larger setup, I can only assume this visual language is shared across the entire product line. Probably good to stay consistent, but it's a bit rough for me personally on a visual level. I could see applying other techniques to help here some.
At the very least, you can probably eliminate some of the redundancies. I don't need to know tables are bold italic. I can see a table is a table without the need for any real call-out there. Similarly, you note items with a symbol, but also with italics. Chapters/Rooms/Important Areas can collapse into a single entry since they share markings. Things like that could shave away some of the cluttered feel to the page. It's actually strange. So many entries I have pointed out how helpful calling out details would be for some key points. Here, I find myself seeing so many things called out that my eye doesn't naturally land on anything.
Clear background, clear goal. Always good to start with. Key faction noted right away, also good. Mystery as a module nature is nice. So many are find items, kill things, fight BBG. Something where the goal is clear, but the details are fuzzy and there's not some obvious target to attack makes for a nice change of pace.
Crime scene is nice. Lots of things to look at, lots of ways for different players to shine by searching. Even missing a clue or two won't be an issue. You might not get the whole picture, but you can see enough of the puzzle to have leads. If it was a larger work, I would add some red herrings (not dead ends, but things that lead down a less direct path to answers) and maybe a few more locations to explore. Given the space constraints, not a huge issue here.
By the second location, I realize the path element can be removed entirely. Every location can lead to every other location. No real reason to include it here. I make it to entry 3 when I realize the linked map doesn't seem to have anything to do with this set of independent locations. Am I missing something or no? And then I see the Cemetery mentions a crypt. Ah.. okay, that's probably what the map is for. From the way it's described, I don't really need a map though. On the fence about the whole map situation at this point.
Anyway, final encounter isn't ridiculous. Balance will probably vary a bit from system to system, but overall I could see the level set noted working for this fight in a lot of the systems I am familiar with. Minimal tweeks needed. All told, there's a lot of chances to use abilities, a lot of times to explore RP, a reasonable set of leads to explore the mystery and a capstone fight to pull it all together. Fair work. Single piece of art at the end isn't doing anything for me, but it's not hurting things either.
I still am surprised at the use of only 3 pages and still feel confused regarding the mention of maps in the explanation page, but no apparent need for a map, nor direct inclusion. Maybe it's me. As I said, the amount of call-out information kind of makes me want to go cross eyed. Items, mysteries, fights, traps. Lot of things in a surprisingly tight package. While I don't know if I'd run this at my own tables, there's certainly a number of things I can take away from this and use in different ways at my table. Sometimes that's more valuable at the end of the day. Thanks for taking the time to participate and for doing something atypical with your adventure!