If you are experiencing problems with graphics like flickering, inverted colours, etc., do the following:
1) Download this archive: files.gog.com/support/TA.zip
2) Extract it wherever you see fit (the program will detect game's installation path)
3) Run TA_Resolution.exe (you may have to right-click it and select "Run as administrator" on Windows Vista/7)
4) Tick the checkbox labeled "Windowed Mode" and select the resolution you want the game to run in. If you select your current screen's resolution the game will look as if it was running in fullscreen mode, but the problems with graphics should be gone!