A character called Gummi gives you a new gadget from time to time which you will use to solve multiple puzzles. They are used with keyboard keys. (They're inspired by Zelda items)
X-Ray Specs This item can reveal hidden items! Use it to reveal concealed keys!
Throwing Star The Throwing Star can open treasure chests, pull levers and collect items from afar
Zippo The Zippo can make you much faster and zap you across huge gaps. It can also give you the ability to smash holes and break certain objects.
And plenty more gadgets!