Thwocker
Thwocker is an unreleased Activision prototype for the Atari 2600, programmed by Charlie Heath, the designer of Reactor. It was worked on in 1984 and has been described as “Joust with musical instruments”: you guide a bouncing little conductor through a maze, collecting notes to build a song. The game was never finished, but it is an odd and charming glimpse of what Activision was working on as the market collapsed. You can play the prototype here in your browser.