Fluxly can access the microphone on your phone if you provide permission. Nothing is done with that recording except within the context of the game, i.e. making sample loops. The sound file is saved to your external storage (Android) or documents directory (iOS).
The apps Noisemusick, DR-OM, Redacted Tower, Cryptozoologic and CGOL do not collect any personal information whatsoever from your use of the app.