Activating this trainer:
If not state otherwise below, press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.

Promo Options:
NumPad3: Unlimited Jumps

Trainer Options:
NumPad1: Unlimited Health
NumPad2: Unlimited Arrows
NumPad3: Unlimited Jumps
NumPad4: Easy Kills

Notes:

Unlimited Health:
Toggle on to try and stay alive.

Unlimited Arrows:
Toggle on for effect.

Unlimited Jumps:
Toggle on for effect.

Easy Kills:
Toggle on and many enemies die very quickly.