Change Difficulty
Use Notepad to edit "default.ini" file (make a backup first!).
Scroll down to the [Difficulty] section and change the values of the
following variables:

AI visual acuity multiplier How well AIs can see
AI auditory acuity multiplier How well AIs can hear
AI tactile acuity multiplier How well AIs can feel
AI hitpoints multiplier All AI starting hitpoints will be
scaled by this
AI-to-player damage multiplier All damage applied to the player
by the AI is scaled by this

For example, set them to 0 (zero) and enemies won''t be able to
see you, hear you and even hurt you.

Disable First-Person Head Bobbing
To disable the up-and-down bobbing motion of the camera use
Notepad to edit file "T3PlayerAnims.ini" (make a backup first!). In
the "-- NORMAL GROUND MOVEMENT --" section change all [Forward1]
through [Forward6] from ''Translate=false'' to ''Translate=true''.

Disable opening movies
To disable opening movies open default.ini file located in the
Thief 3System folder using Notepad (make a backup first!). In the
"[PCStartup]" section change the ''ShowIntroMovies=True'' line to
''ShowIntroMovies=False''. Now when you start the game, you''ll be taken
directly to the loading screen.

Disable loadscreen tips and loadscreen flavor text
Use Notepad to open ''HelpText.sch'' file located in the Thief
3ContentT3BooksEnglish folder (make a backup first!). Select all
the text, delete it, and then save the changes. This will loadscreen
tips.

To disable flavor text that appears on the loading screens, you
need to open ''Quotes.sch'' file located in the Thief
3ContentT3BooksEnglishString_Tags folder using Notepad (make a
backup first!). Now you need to replace each quote with a " " (a
space; do not leave an empty string, or you''ll get a message about
having no messages to display). Save the changes. Note that removing
these quotes may cause you to miss out on certain details of the
story, so keep this in mind.