TL;DR: a patch has just been made live. It's pretty big (because the engine was updated too).
The last update to Sickness introduced a bug which made Sara's good ending inaccessible. Worse, it spoiled another route... for a character who may not have even shown up!
Unfortunately, bug reports and support requests have always gone to Sickness' publisher rather than me (the developer) personally. For the same reason, I haven't been checking the discussions, as they would always identify any issues and pass them along to me. Which worked great... until it didn't.
I was made aware of this bug about 20 minutes before the patch went out, when someone reached out to me directly via Twitter. I was able to find and fix the bug fairly quickly, and it's a very minor change. The bug was caused by a behavior of the Renpy engine I didn't know about with regard to "from _call" statements... not that anyone asked.
While the fix itself is very minor, however, the patch is not. I kept the version of Renpy with which Sickness was made for a year and a half. After the last update, I removed it in favor of the newest build of the engine. The patch I just released was made with this new version of the engine, which means things that haven't been changed within the game still need to be reuploaded because they were recompiled with the new engine.
Anyway, so this doesn't happen again, I've updated the support details for Sickness. They should now lead to me directly rather than going through Sickness' publisher. Please send any bug reports via email or twitter, as I do not tend to check Steam discussions.
I hope it doesn't sound like I'm trying to throw the publisher under the bus, but I thought you deserved a proper explanation rather than me just saying "Fixed!" and moving on.
I should have kept a closer eye on things, but I grew complacent after having someone else deal with these matters in my place for such a long time. This is my mistake, and I apologize for the lack of communication.