Sentris (opens in new tab) is a rhythm puzzle music creation type game that looks a bit like Simon Says (opens in new tab) if it was being played by those little alien fellas from Close Encounters of the Third Kind. Images and trailers show a game that seems strange and abstract in all the best ways, but we don't need to look at those any longer to surmise what it's all about, because Sentris is now on Steam Early Access. Look at it there, all early and accessible (opens in new tab) .
I'm going to refrain from tripping over myself in an effort to explain Sentris any further; the following video should do a better job of clueing you in.
See, I wasn't being facetious when I mentioned Close Encounters earlier—there's something about the flashing lights and Simon Says music and desert landscape that reminds me of the final scene in Spielberg's famous mashed potato film. To go into a bit more detail, Sentris recently cleaned up on Kickstarter to the sum of $56K; the game you see on Early Access is "core-complete" with several puzzle levels, guitar, bass, synth and drum instruments, and a few different backgrounds, but the full release will feature more of everything, plus local multiplayer, a level editor and Steam Workshop support, and the ability to export your music as a WAV file. Devs Timbre Interactive expect the game to be finished "before April 2015".