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:

Numpad 1: No Damage

Numpad 2: Unlimited Stamina/Energy

Numpad 3: Unlimited Ammo

Numpad 4: No Reload

Numpad 5: Add Zorkins Currency

Numpad 6: Unlimited Oxygen Underwater Swimming

Numpad 7: Easy Resources Gathering

Notes:

Numpad 1: No Damage - toggle this on and the trainer will try to keep you safe from most damage.

Numpad 2: Unlimited Stamina/Energy - toggle on and the trainer will try to keep the meter full.

Numpad 3: Unlimited Ammo - toggle on and if you have ammo and reload, it won't decrease most weapons.

Numpad 4: No Reload - toggle on and when you fire most weapons, the current clip count will not decrease.

Numpad 5: Add Zorkins Currency - each press adds more.  You need to have gathered at least one for it to work, and also you may need to gather or spend some to see it change.

Numpad 6: Unlimited Oxygen Underwater Swimming - toggle on and you can swim underwater indefinitely.

Numpad 7: Easy Resources Gathering - toggle on and when you gather items like shells or red crystals, etc, you will have the maximum amount possible.