I am pretty sure that its the same problem with the GOG version.
Option 1: open a console/terminal and start the shell-script with 'LANG=C ./shell_script'
Option 2: edit the shell script and add the line 'LANG=C' somewhere above where it starts the main executable
If you have a desktop shortcut to start the game you can edit that one instead, but since I don't know which desktop you use I can't give you detailed instructions how to do that.
To elaborate the problem, game resources stores some values with a decimal point ( example 1.45 ), now the game reads that value out of the resources on your hdd, your localisation defaults to a language which uses a commata instead of a decimal point ( so value should be 1,45 ) but since its stored with a point the read on the value transforms it to 145 since there is no commata. With the environment variable LANG you tell the program to disregard your default language setting and fall back to english with a decimal point.
