To enable cheats within the game first locate the hitmanbloodmoney.ini file and open with Notepad (backup first). Add the line EnableCheats at the bottom of the file and save it.

Whilst in the game press the C key and enter the following codes:

Show OSD 1 or 0 .... HUD toggle.
Invisible Mode 1 or 0 .... Toggle AI Sense Player.
God Mode 1 or 0 ... Agent 47 takes no damage.
InfAmmo ... Set ammo to integer value. Unknown if integer will affect code.
InfClip .... Set magazine capacity to limitless.
Test Cloth ... Randomly changes player clothing to random skin in set stage. Complete Level .... Clears current mission.
Time Multiplier .... Time compression/expansion.
Teleport ... Random player spawn.
Beam here ... Spawn player at selected area on map (map open?).