Another query for the experts out here. I have seen a cheat which talks about pressing F4 and entering a code to unlock the Nazi Knife. On pressing F4 there is no option to enter any code!!!
Strangely when I played the game the first time, I at some point got the Nazi Knife because whenever I did a stealth kill, the protagonist took out a long knife and stabbed the Nazi's on the right side somewhere between the ribs or something. I have no idea how I got it or how to get it now. Waiting for your help...