voodoo47: while being able to clean up ddfix end enable/disable fixes is nice, it lacks the most important thing - the dml fixes. without them, there will be some pretty serious issues in some levels (they should not prevent you from completing the game, but they are still quite unpleasant).
I have already submitted a basic NewDark Thief Gold patch to GOG (I did the same thing for the
GOG release of SS2), it should be available soon, so I don't think this installer is necessary (for the GOG version, anyway).
//also, 1.16 is up, the Mage Towers dml fix is included, plus some more small tweaks, also added a USERMODS folder - if you have any texture packs you want to add on top of everything from TFix, that's the place. 1.16 should be the last cleanup release before the big overhaul.