Activating this trainer:

Press F1 at main menu.

Listen for 'Trainer Activated'.

Press desired hotkey. All hotkeys can be changed on the trainer.

Trainer Options:

NumPad1: Infinite Health

NumPad2: Infinite Flashlight

NumPad3: Unlimited Ammo

NumPad4: Stealth Mode

Notes:

Stealth Mode:

While active enemies will not see or hear you.

But if you hit them (or touch them) they will react to you.