I'm a little bit confused with all these patches. I thought the GOG version was patched up and made ready to run, using DDFix and no longer requiring the registering of the Indeo video codec to get cutscenes to play. Is this the case?
So, as the GOG Thief installer versions are all still the 1.0 versions, what is the recommended steps to install Thief 1 and Thief 2? And when we get the 2.0 versions, do we have any idea on what changes GOG might be making?
The GOG versions have DDfix, which fixes some problems; patch 1.19 fixes everything DDfix did and has many additional improvements (including integrated video decoding--DDfix still relied on the original Indeo codecs). The installation procedure is very simple:
For Thief Gold, install the game followed by TFix
For Thief II, install the game followed by Tafferpatcher
("TafferPatcher_TMA_207_beta", or whatever is newer by the time you read this).
For both patch installers you can pick and choose the components you want. The installers list some features that aren't necessary (e.g. better textures) so you can uncheck those if you're wanting the purest experience. For Tafferpatcher you want the Patch 1.19 option if nothing else (TFix always installs this).