The Sun and Moon (2014)

The Sun and Moon, the winner of Ludum Dare 29, is a platformer with a unique mechanic: you can dive into the ground. Momentum is conserved but gravity is reversed, letting you fling yourself high into the air or deep beneath the surface. The goal is always straightforward - collect the three orbs in the level and jump into the wormhole - but spikes, endless drops and impossible heights make this more and more difficult.