Make a backup of this file before proceeding to edit anything. Use notepad or a text editor to edit the file hitman2.ini. At the end of the file add enableconsole 1

Now start a game and during gameplay press ~ to get the console and enter a code below

infammo - Unlimited ammo
invisible 1 - Invisibility
god 1 - Invincibility
giveall - All weapons

IOIRULEZ Invincibility
IOIGIVES Weapons & Ammo
IOIHITLEIF Max out health
IOIER Bomb Mode
IOISLO Slo-Mo Mode
IOIHITALI Ali Mode
IOILEPOW Lethal Charge Mode
IOIGRV Gravitation
IOINGUN Nailgun Mode
IOIPOWER Mega-Force