Well these patches seem to have come out of nowhere. Looking at the patch notes, it makes me wonder if whoever made this had access to the source code for the engine. Whoever did it, I thank you!
The patch has made some massive improvements for System Shock 2. For example, more resolution options have been added, the video codec has been replaced with FFmpeg decoder (so the videos always work now), and we have EAX audio back. This is only the tip of the iceberg though. Check the patch notes below.
I have also updated my instructions for Getting System Shock 2 Working & Looking Great
This is an unofficial patch for Thief II: The Metal Age (T2) which updates the game from v1.18 to
v1.19, providing improved support for modern hardware and correcting many known bugs. T2 can be
purchased digitally from GOG (www.gog.com) and Steam (store.steampowered.com). If you prefer a
boxed copy, it can usually be found on Mastertronic and Amazon (or similar).