DIE2HARD

Hi people,i'm Alex and first i want give my excuse for my bad english,but i'm italian.I see that forum for more times and now i want ask one match for all people there.
I play in that game from more times and i have seen people who hack that,i have tried to hack but without results.

http://die2hard.com/

I have seen that hack like speed run,i have try cheatengine without results and i have seen people who fly in the sky,and i think that this is impossible for all understand that hack.

http://www.youtube.com/watch?v=ythFp78mNLA

someone can do that hack?Can fly in the sky?

I hope that someone can explain me,too i think is a very difficult hack.
Thx people
Best regards

Alex