The Stanley Parable - The Stanley Parable is an Action, First-person Perspective, Puzzle-Platform, Exploration and Single-player video game created and published by Galactic Cafe.
Flowkey - The easiest way to learn piano with your iPhone or iPad
Antichamber - "A game with half of the attention to detail and imagination Antichamber has would be a smash hit - this bare-bones first-person puzzler is one of the most thought-provoking, engaging, and challenging video games ever developed.
Yousician - Learn to play music at home, at your own pace
Quantum Conundrum - Quantum Conundrum is a First-person Perspective game with strong Sci-fi, Puzzle-Platform, and Single-player elements published by Square Enix and developed by Airtight Games.
Melodics - Melodics is a desktop app that teaches you to play MIDI keyboards, pad controllers, and drums.