Fatal Subject is an alternative ruleset for Shudderspeed that turns the game from a speed and dexterity test into a scavenger hunt.
The single page of rules is a .png, and loosely follows the Shudderspeed format, but with some nice magenta subheadings to provide visual contrast and break up the page. Everything is clean and readable.
Contents-wise, this one change adds a ton of depth to gameplay. With a few minutes to prepare a room, a GM can set up a whole battle. And the hiding of healing tokens and damaging objects, the GM has even more levers with which to control game difficulty.
Honestly, my favorite thing about Fatal Subject is that it fully lays the ground work for a Shudderspeed LARP, should you want to run one. All you need is a reasonably spooky location, a few curated rooms, and a facilitator to check people's scores, and Fatal Subject has you covered.
Overall, if you want to make Shudderspeed's combat more scavenger hunt-y, or if you simply want to give players some other things they can photo during ghost fights, definitely give Fatal Subject a read. It's a small change to the rules, but it has a huge and excellent ripple effect.