It's made in GameMaker and for some reason lots of anti-virus programs think games made in GameMaker are malicious. You can just hit ignore and continue if you're getting it from Defender, I can assure you that it isn't a virus. It would have been taken off of itch and Steam years ago if it were a virus.
To explain this further, most GameMaker games don't have a publisher listed in their metadata. That doesn't mean that it's a virus, it just means it isn't published by Microsoft or Sony or some other well known publisher. Anti-virus programs seem to correlate no publisher or no well know publisher with VIRUS though.