Hi, I just completed the Tomb Raider Legend game on easy as well as two time trials unlocking the one shot kill and Excalibur. Now I would like to play it through on hard to get the Hard Adventure achievement and be able to access these extras/codes while playing. However, when I start a new game on hard difficulty, and enter the codes, they don't appear to work. I can go into my Bolivia Redux save and select any level to replay on hard, input the codes and access the one shot kill and Excalibur but when I start a new game, it does not recognize the codes. Is there a step that I am missing that would allow me to play a new game through on hard and still have access to one shot kill etc ? Thanks !

I was wondering the same thing.  I completed the Bolivia Redux time trial for the one-shot kill code.  The next night, I re-entered an old, saved game on hard at the final battle in Japan that I could never get past on hard.  I successfully entered the one-shot kill code and took out the Japanese boss straight away.  (That was so satisfying!)  I saved/quit the game at that point and tried to start Africa yesterday, but I couldn't enter the code again.   I tried replaying and winning the Bolivia Redux time trial and re-entering the code to no avail.  I'm just not talented enough to get past the game on hard without help from the unlock codes.