Heya,
From what I can tell through Googling, the SONAR.etc alert appears to be a semi-frequent false positive result with games made in GameMaker. The latter, I cannot find any results at all about. The native game should not be accessing any area of your PC other than Localappdata (for storing your save file), and needless to say, there're no harmful files in Revolver and Co. Besides save files, everything in the game happens locally and offline.
My recommendation would be to perform a thorough scan of your PC just incase you have anything malicious hijacking .exe downloads, then delete Revolver and Co as you downloaded it and try redownloading it again and see if the issue repeats. If it does, you could try reporting it to Norton as a false positive.
Let me know how things progress, am happy to help out further.
Allison James
Chequered Ink Ltd