Always make a backup copy before making any changes. Open the file 'gothic.ini' with any text editor, and change 'bbloodDetail' from 1 to 3 for Blood Mode. Also, change test mode from 0 to 1 to activate the ingame cheats:

F2 - Console

cheat god - God Mode
cheat full - Health

H - Hurt Yourself
K - Vanish in the Ground
Z - Spin Around

F3 - Windows Mode
F4 - Normal Mode
F5 - Immobile Camera
F6 - Mobile Camera
F7 - Cycle Through Game Sections
F8 - Health/Mana Refresh