itch.io

It does that with most applications it doesn't recognize. It's normal with fangames.

Windows and many antiviruses began doing their work relatively bad. They flag any new exe that isn't signed by them as a virus. While I get the concept in general, it's still a flawed one that creates a sea of false positives.

I can't do much, other than state that it's 4 years and counting that this keeps happening. I have better things to do than tarnish my reputation with a virus on a game I poured years of work into.
Flag the file as a false positive, and allow it to run if you'd like to play the game.