INTRODUCTION
Original cutscenes arrived in 640x480 and 320x240 resolutions, the new HD cutscenes are all encoded at 1280x960 with special sharpening process applied that restores certain details. It is technically impossible to obtain video quality out of thin air (except in C.S.I. TV series hehe), but this is probably the closest thing we can get with current technology and certainly far better results than with Bicubic or Lanczos resampling.

PREVIEW SAMPLES (sort them by name)*:
http://s14.photobucket.com/user/rejzor/library/SS2HDC?sort=3&page=1

*Actual in-game quality may vary due to video scaling engine used by the game as well as screen size/resolution.
But if you feed it higher resolution video, it will do less of its crappy scaling...

INSTALLATION
Go to:
.\System Shock 2\Data\cutscenes

First backup all the original videos and replace them with new HD videos. They are named the same, just overwrite them.

DOWNLOAD & MORE INFO:
https://rejzor.wordpress.com/2015/05/26/system-shock-2-high-definition-cutscenes/

Let me know what you think :)

just like on TTLG, I'll comment on the technical side of things - feeding the Dark videoplayer which supports max 640*480 with videos four times larger is a VERY bad idea.

Let people do whatever they want with their game.

it's not like I can prevent people from doing what they want.

It's not so much a bad idea as it is a complete waste of effort. Low-res video, scaled up to high-res, then scaled back down to low-res. May as well have not even bothered.