Stargoat

Waveform has you flying a particle through various space-themed levels, collecting little orbs of 'light', among other things. The catch is, the particle will only travel along a sine wave - of which the player can manipulate the amplitude and frequency, providing the primary way to control the particle's position. While the levels are rarely difficult to complete on the most basic level, completionists and those looking for a challenge will enjoy attempting 100% completions of the levels. With a well developed, intelligent mechanic, challenging gameplay for those who seek it, and a relaxing atmosphere, Waveform is an excellent game well worth checking out.