Way back when, I realized that even Sin 1.11 (final patch) had minor glitches, but that these glitches could be fixed. So I made my own "complete" patch which worked beautifully with my recent Sin SP game re-experience.
Here's what the readme says:
This patch fixes the following:
1) New demos and a fixed demo player script. I have recorded some demo footage from various levels that show some more action and story than Ritual's default demos that came with the first patch (and replaced the out-of-date, but much better demos of version 1.00). The Ritual logo and intro movie are no longer played before the demos are started.
2) Direct menu access without login request after intro movies (for profiles named "blade"). Players who run Sin alone on their own computer no longer have to log in to the game, avoiding its multi-profile system. See the notes for details.
3) Fixed cine_elexis model definition file, now supports nude skin.
4) Fixed dialogs in chem2, hdocks and uwpass. Some of the dialogs in these maps were either cut short or missing speech (the start of uwpass only showed text, but didn't play speech). Locating appropriate dialog audio in the pak files, I extended respectively fixed these dialogs.
5) Fixed "action" music issue with cinematics, now plays properly. The "action" part of the interactive soundtrack did not play any longer in cinematics after the first patch. This was corrected by using the "forcemusic" command in the cinematic scripts.
6) Cinematic music has lower volume now for higher dialog volume. On the default audio volume mix of Sin, the music is well below the sound effects and speech, but in cinematics most of the music is too loud and overdubs the speech. I reduced the cinematic music's volume so that the speech is clearly hearable again.
7) Included Ritual's readme file for CTF which was added with the 1.04 patch but removed from later patches (including the cumulative 1.00 to 1.11 patch).
The file also explains what I fixed about the profile system and how to handle this fix.
I uploaded this patch to my own webspace, it's 6.20 MB in size and zipped only. Read the readme, then extract the contents to your Sin folder.
Get Sin Complete Patch