Pixle (not to be confused with Pixle) is an artistic one button game that was probably inspired by Helicopter, but alters and improves on the formula to create a beautiful, if coffee break sized, experience.
The game's author, Stellar-Ø, describes the main character, Pixle, as "a mysterious multi-form shade", and as he flies through a beautifully drawn forest, it's up to you to help him find those other forms. Pixle never stops moving or changes his speed, but the actual steering comes down to you as he flies at the same height as your mouse pointer. To keep Pixle flying high, soar over seeds for a boost of energy, and left-click to nab crystals that unlock new evolutionary forms more advanced than your humble beginnings. At full power, you can hold the left mouse button to trigger a fast and powerful Overdrive Mode, but don't get cocky; miss a crystal at any point in your flight and everything from Pixle's combo and speed to his evolution will be reset.
The game doesn't last long, so your time with Pixle will be like the character's time in his world, and indeed, the game itself: short but beautiful.