What are some alternatives?
When comparing Incredibox and Ramsophone, you can also consider the following products
Audiosurf - Audiosurf is a music-adapting puzzle racer where you use your own music to create your own experience.
Splice Beat Maker - Make and share beats in your browser
Rocksmith - Rocksmith builds off of the fundamentals of music games like Rock Band and Guitar Hero by offering fundamental lessons in actually playing guitar.
Sampulator - Make (and record) beats on your keyboard
StepMania - Rhythm game for Windows, Mac, and Linux.
Super Looper - Make music in your browser