AlienMind: Never played SiN for more than 30 minutes because it had un-disable-able mouse acceleration (i mean it not even with ini files) and mouse-controlled like molasses so I said fuck it and unistalled it.
ZFR: Oh yes, that's the only thing I had to fix (though for me even withought the fix it played well, the mouse was fast, I just preferred the speed to be even).
Anyway, the problem is not with the game itself, but because Windows changed the way it handled mouse-acceleration/"precision" from 7 onwards as opposed to XP. This affected many games from that era, including Half-Life, Unreal and Quake 1 + Quake 2 (the engine of which SiN uses).
For technical details about the problem and a fix:
http://donewmouseaccel.blogspot.com/2010/03/markc-windows-7-mouse-acceleration-fix.html Thanks to:
https://www.gog.com/forum/sin_gold/mouse_accelerationlazy_mouse/post9 Thanks for the fix, but definitely won't do
[HKEY_CURRENT_USER\Control Panel\Mouse]
"SmoothMouseXCurve"=hex:\
00,00,00,00,00,00,00,00,\
15,6e,00,00,00,00,00,00,\
00,40,01,00,00,00,00,00,\
29,dc,03,00,00,00,00,00,\
00,00,28,00,00,00,00,00
"SmoothMouseYCurve"=hex:\
00,00,00,00,00,00,00,00,\
b8,5e,01,00,00,00,00,00,\
cd,4c,05,00,00,00,00,00,\
cd,4c,18,00,00,00,00,00,\
00,00,38,02,00,00,00,00
on my Windows 7 system because basically I'm too old for this shit now ;) If you asked me 20 years ago I would gladly format my hard drive with some extra option just to see if it's 1% faster and such plus spend the corresponding 42 hours to put everything back because there were some read errors :)