This oozes with personality from start to finish. Beautiful choice of fonts, colors, and use of illustrations. I think you really nailed keeping a consistent theme and mood throughout the booklet.
I really enjoyed the read. The murders were interesting and plausible for players to solve. The legs hanging from the ceiling has a great pay off running into their upper halves.
I liked that the set up had the players already in debt, working to pay that off. It would play well with the 'carousing' rule used in a lot of OSR campaigns and the scenario presented could be a great change of pace, but a GM might need to do a bit of work to fit a more typical fantasy setting.
I thought the Table of Contents was brilliant, but I'd like to see those images repeated on the pages they represent so a reader can quickly jump to what they're looking for - a bonus would be if the images were clickable to jump straight to that page.
I think I may be misreading this on pg. 2, but is the door intended to be locked? "An ‘OPEN’ sign hangs crookedly on the front doors (pg. 5). However, still unlocked."
I would recommend cutting this from the description on the first page: "The formatting borrows from standard screenplay writing but prior experience with film scripts is not necessary. Just know that" as well as "and for each NPC that speaks we’ve included a sample dialogue" - keeping just the note about INT. and EXT. At least for me, it set an expectation that reading the booklet might be difficult, when in reality it's very intelligently laid out.
You also might want to consider putting " " around the NPC sample dialogue, despite that language I suggested cutting, I've just been trained that unquoted text under a portrait is a description.
I liked the included random tables, especially for the coat check, and the options for pursuing Cleo to extend or conclude the adventure.