Those eyes are either cold and dead... or full of divine majesty. Our money's on the latter. Gravity Duck can control gravity, one of the most powerful forces in our world. He has been charged with collecting 40 golden eggs. Easy.
Run about flipping gravity when you see fit. Use gravity puddles to flip the gravity sideways where available and avoid all the evils. Get to the eggs on an even playing field and you'll be in for the win.
Use the arrow keys to move and 'x' to flip gravity.
You can't jump so concentrate on where you are landing to make sure it's where you want to be.