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.

Trainer Options

# Player 
     NumPad1: Super Jump
     NumPad2: Unlimited Inventory Items
     NumPad3: Enable Developer Cheats

# Game  
     NumPad4: Game Speed

Editor Options

# Player 
     Item Pick-up Multiplier

# Inventory 
     Slot 1 - Slot 10

Notes

Enable Developer Cheats:
Enable this option then press 'CTRL + SHIFT + J' to bring up the developer console.

Inventory Slot 1 - Slot 10:
Press 'Tab' so the editor could fetch the itmes, it might not work if the current quest is already completed.